Add color support for errors/warnings etc.
In class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine:
* ConsoleLogger.cs: Use ColorSetter and ColorResetter .
Support 'XBUILD_COLORS' to set colors for errors, warnings,
events and messages.
In tools/xbuild:
* Main.cs: Add support for emitting messages in color.
Taking relevant code from mcs/report.cs . Using ANSI
color codes here instead of Console.ForegroundColor
because of a bug in Console.
git-svn-id: svn+ssh://mono-cvs.ximian.com/source/trunk/mcs@143902 e3ebcda4-bce8-0310-ba0a-eca2169e7518