added a few more plotting packages

[cormullion]

Ref: GiovineItalia/Gadfly.jl#658

[ihnorton]

This page is not intended to be a grab bag of plotting libraries, but rather a recommendation of a small number of the best options for new users. The proposed list does not seem to have been even minimally vetted, as it lists things like julia-plot which has not been maintained in years, and several others that are clearly not appropriate to recommend to new users.

[ihnorton]

A few thoughts on the proposed list:

Yes: Winston
Maybe: one of Bokeh or Vega

No (non-local, requires external accounts): Plotly, Google Charts
No (insufficient benefit over other options): Gaston, QWT
No (not yet generally usable): GLPlot
No (too niche / minimal / unmaintained): TextPlots, ASCIIPlots, Sparklines, Hinton, ImageTerm, julia-plot

[ViralBShah]

I would not mind having a different page that lists all of these, or a blog post that compares all these, that we link - but this page should just recommend 2-3 different and well functioning options.