Tweak the interface for analyzing the CF conventions for a name

Tweak the interface for analyzing the CF conventions for a name
to take a FunctionDecl* instead of an llvm::StringRef.  Eventually
we might push more logic in there, like using slightly different
conventions for C++ methods.

Also, fix a bug where 'copy' and 'create' were being caught in
non-camel-cased strings.  We want copyFoo and CopyFoo and XCopy
but not Xcopy or xcopy.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140911 91177308-0d34-0410-b5e6-96231b3b80d8