Moved content of cppinsertdecldef.(cpp|h) cppcompleteswitch.(cpp|h)
cppinsertqtpropertymembers.(cpp|h) and ApplyDeclDefLinkChanges to
cppquickfixes.(cpp|h).

Made msgQtStringLiteralDescription private member function of
WrapStringLiteral, added anonymous namespace, "extracted" useful
functions to the top of cppquickfixes.cpp.

Change-Id: I4f82a005a62be3c29d4b96902667bd3a2b9397cc
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>