plotColumns.m: plots columns in matrix as time series

Plots matrix columns w/options

[h,varargout]=plotColumns(data,varargin)
plots columns of a matrix as if each column is a time series

USAGE:
plotColumns(data);
[h] = plotColumns(t,data);
[h] = plotColumns(t,data,{colors});
[h] = plotColumns(t,data,'plotopt');
[h] = plotColumns(...,'plotopt');
[h] = plotColumns(...,{colors});