Another attempt to add a clang-tidy check for flagging C-style casts.

Summary:
The first version failed the SubstNonTypeTempateParmExpr-related test
on some buildbots. This one uses the new substNonTypeTempateParmExpr matcher to
filter out implicit C-style casts.

This patch depends on D4327.

Reviewers: djasper

Reviewed By: djasper

Subscribers: aemerson, cfe-commits

Differential Revision: http://reviews.llvm.org/D4328