Add some missing diagnostics for C++11 narrowing conversions.
Remove sparse text on diagnostic options.  These are not really documented anywhere, and they really aren't for normal users.
PR15095: Use more correct source locations for the InitListExpr we fake up for
vector initialization. Patch by John Stratton!
Test for virtual instead of pure here. It has the exact same effect, and John
claims it will improve performance.
Remove dead code related to the now defunct PCH stat cache.
Revert "Remove sparse text on diagnostic options.  These are not really documented anywhere, and they really aren't for normal users."

I changed my mind.  We should just document these in the man page.
Spaces instead of tabs.
Driver and option support for -gsplit-dwarf. This is a part of
the DWARF5 split dwarf proposal.
TextDiagnostic.cpp: Suppress a warning to use ptrdiff_t on i686-clang. [-Wsign-compare]