Merging r203050:

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r203050 | rtrieu | 2014-03-05 20:09:03 -0500 (Wed, 05 Mar 2014) | 4 lines

Change the color of comment nodes from bright yellow to blue.  Bright yellow on
a white background is difficult to read.  Also include a chart showing which
colors are used by which elements in the AST dump.

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llvm-svn: 205786