FT_MULTIPLOTER plots the event-related potentials or event-related fields verus
 time, or the oscillatory activity (power or coherence) versus frequency. Multiple
 datasets can be overlayed. The plots are arranged according to their location
 specified in the layout.

 Use as
   ft_multiplotER(cfg, data)
   ft_multiplotER(cfg, data, data2, ..., dataN)

 The data can be an event-related potential or field produced by
 FT_TIMELOCKANALYSIS, a power spectrum produced by FT_FREQANALYSIS or a coherence
 spectrum produced by FT_FREQDESCRIPTIVES.

 If you specify multiple datasets they should contain the same channels, etc.

 The configuration can have the following parameters:
   cfg.parameter     = field to be plotted on y-axis, for example 'avg', 'powspctrm' or 'cohspctrm' (default is automatic)
   cfg.maskparameter = field in the first dataset to be used for marking significant data
   cfg.maskstyle     = style used for masking of data, 'box', 'thickness' or 'saturation' (default = 'box')
   cfg.maskfacealpha = mask transparency value between 0 and 1
   cfg.xlim          = 'maxmin' or [xmin xmax] (default = 'maxmin')
   cfg.ylim          = 'maxmin', 'maxabs', 'zeromax', 'minzero', or [ymin ymax] (default = 'maxmin')
   cfg.gradscale     = number, scaling to apply to the MEG gradiometer channels prior to display
   cfg.magscale      = number, scaling to apply to the MEG magnetometer channels prior to display
   cfg.channel       = Nx1 cell-array with selection of channels (default = 'all'), see FT_CHANNELSELECTION for details
   cfg.refchannel    = name of reference channel for visualising connectivity, can be 'gui'
   cfg.baseline      = 'yes', 'no' or [time1 time2] (default = 'no'), see FT_TIMELOCKBASELINE or FT_FREQBASELINE
   cfg.trials        = 'all' or a selection given as a 1xN vector (default = 'all')
   cfg.axes          = string, 'yes' or 'no' whether to draw x- and y-axes for each graph (default = 'yes')
   cfg.box           = string, 'yes' or 'no' whether to draw a box around each graph (default = 'no')
   cfg.showlabels    = 'yes' or 'no' (default = 'no')
   cfg.showoutline   = 'yes' or 'no' (default = 'no')
   cfg.showscale     = 'yes' or 'no' (default = 'yes')
   cfg.showcomment   = 'yes' or 'no' (default = 'yes')
   cfg.comment       = string of text (default = date + limits)
                       Add 'comment' to graph (according to COMNT in the layout)
   cfg.limittext     = add user-defined text instead of cfg.comment, (default = cfg.comment)
   cfg.fontsize      = font size of comment and labels (default = 8)
   cfg.interactive   = 'yes' or 'no', make the plot interactive (default = 'yes')
                       In a interactive plot you can select areas and produce a new
                       interactive plot when a selected area is clicked. Multiple areas
                       can be selected by holding down the SHIFT key.
   cfg.renderer      = 'painters', 'zbuffer', ' opengl' or 'none' (default = [])
   cfg.linestyle     = linestyle/marker type, see options of the PLOT function (default = '-')
                       can be a single style for all datasets, or a cell-array containing one style for each dataset
   cfg.linewidth     = linewidth in points (default = 0.5)
   cfg.graphcolor    = color(s) used for plotting the dataset(s) (default = 'brgkywrgbkywrgbkywrgbkyw')
                       alternatively, colors can be specified as Nx3 matrix of RGB values
   cfg.directionality = '', 'inflow' or 'outflow' specifies for connectivity measures whether the
                       inflow into a node, or the outflow from a node is plotted. The (default) behavior
                       of this option depends on the dimord of the input data (see below).
   cfg.layout        = specify the channel layout for plotting using one of the supported ways (see below).

 For the plotting of directional connectivity data the cfg.directionality option
 determines what is plotted. The default value and the supported functionality
 depend on the dimord of the input data. If the input data is of dimord
 'chan_chan_XXX', the value of directionality determines whether, given the
 reference channel(s), the columns (inflow), or rows (outflow) are selected for
 plotting. In this situation the default is 'inflow'. Note that for undirected
 measures, inflow and outflow should give the same output. If the input data is of
 dimord 'chancmb_XXX', the value of directionality determines whether the rows in
 data.labelcmb are selected. With 'inflow' the rows are selected if the
 refchannel(s) occur in the right column, with 'outflow' the rows are selected if
 the refchannel(s) occur in the left column of the labelcmb-field. Default in this
 case is '', which means that all rows are selected in which the refchannel(s)
 occur. This is to robustly support linearly indexed undirected connectivity
 metrics. In the situation where undirected connectivity measures are linearly
 indexed, specifying 'inflow' or 'outflow' can result in unexpected behavior.

 The layout defines how the channels are arranged and what the size of each
 subplot is. You can specify the layout in a variety of ways:
  - you can provide a pre-computed layout structure (see prepare_layout)
  - you can give the name of an ascii layout file with extension *.lay
  - you can give the name of an electrode file
  - you can give an electrode definition, i.e. "elec" structure
  - you can give a gradiometer definition, i.e. "grad" structure
 If you do not specify any of these and the data structure contains an
 electrode or gradiometer structure, that will be used for creating a
 layout. If you want to have more fine-grained control over the layout
 of the subplots, you should create your own layout file.

 To facilitate data-handling and distributed computing you can use
   cfg.inputfile   =  ...
 If you specify this option the input data will be read from a *.mat
 file on disk. This mat files should contain only a single variable named 'data',
 corresponding to the input structure. For this particular function, the
 data should be provided as a cell-array.