Eliminate UnaryTypeTraitExpr

Remove UnaryTypeTraitExpr and switch all remaining type trait related handling
over to TypeTraitExpr.

The UTT/BTT/TT enum prefix and evaluation code is retained pending further
cleanup.

This is part of the ongoing work to unify type traits following the removal of
BinaryTypeTraitExpr in r197273.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198271 91177308-0d34-0410-b5e6-96231b3b80d8
Remove an unused diag left over from r198046

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198272 91177308-0d34-0410-b5e6-96231b3b80d8
Update the copyright credits -- Happy new year 2014!

FIXME: Dragonegg may be updated at non-trivial changes.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198274 91177308-0d34-0410-b5e6-96231b3b80d8