ENH: Use colorbrewer for discrete coloring
ENH: Remove unnecessary *1 and fix 1, 2 categories
Merge branch 'master' of git://github.com/biocore/emperor into issue-299
Merge branch 'master' of git://github.com/biocore/emperor into issue-299
ENH: Use different colormaps for coloring

Using chroma we can use colorbrewer colormaps for gradient coloring.
I've moved the choose-color function into the util.js module and more
importantly I have removed the dependency on THREE.Color class. We were
loosely using this class and converting back and forth everywhere, and
we didn't need to do this.

The licenses for colorbrewer and for chroma were added to the LICENSE.md
file.
BUG: Fix bug with one color in continuous maps
TST: Fix tests to match the new discrete colors
TST: Add test for getColorList
DOC: Add note about colorselection

Add a note about the fix of #161 and #299.
TST: Fix tests for test_format.py
TST: Fix tests in test_core.py
DOC: Add a note about the rainbow colormap.
ENH: Remove discrete/continuous coloring checkbox

This checkbox was needed to select the coloring scheme that was used in
the plot. Since we can now select from a variety of different
colorschmes, I've added discrete-coloring to this drop-down and made it
the default.

This required that getColorList was updated to take only two arguments.
DOC: Update ChangeLog.md file
Merge pull request #309 from ElDeveloper/issue-299

Add color brewer as source for all colors in Emperor