Summary:
In Preparation for graph comparison, this patch breaks out the color
choice code from xray-graph into a library and adds polynomials for
the Sequential and Difference sets from ColorBrewer.
Depends on D29005
Reviewers: dblaikie, chandlerc, dberris
Reviewed By: dberris
Subscribers: chandlerc, llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D29363
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296210 91177308-0d34-0410-b5e6-96231b3b80d8
