phobos commit, revision 1654


user: rsinfu

msg:
std.traits: Added workaround for compiler bug 4333.
Added unittests for regression bug 4312 (caused by bug 4333).  This regression bug is just workarounded, not fixed, so I don't mark it as fixed.  The bug 4312 will be closed when compiler bug 4217 or 4333 is fixed (these are blockers against this regression 4312).
Made some templates to print error message on failure, rather than just failing instantiation.

http://www.dsource.org/projects/phobos/changeset/1654