Add Charting -> XChart

[lonelyjoeparker]

Add charting (histogram, xy scatter) functionality for alignment comparison stats, via Xchart

For alignments:

• [x] first wireframe
• [x] decide on plot types (may involve playing in r)
  • [x] implement automatic hist / scatter detection and plotting
  • [x] implement log / linear switching
  • [x] implement overlay / fresh plot switching Dropped to #56
  • [x] save plots as image Dropped to #55
• [x] check working for all data (column) types / write table model
• [x] implement bivariate scatter

For phylogenies: Push back to 0.9.1+

• [x] decide on plot types (may involve playing in r)
• [x] check working for all data (column) types / write table model Push back to 0.9.1+
• [x] implement bivariate scatter Push back to 0.9.1+ ~~

[lonelyjoeparker]

Simply decided to plot histogram (univariate data) and scatter (bivariate data). But will use checkbox flags to control plotting...

[lonelyjoeparker]

Closing - pending enhancements for 0.9.1+