C++: fix encoding/conversion of built-in macros

Task-number: QTCREATORBUG-9404

Change-Id: I732b729e64b065b4ac75c547d9370cbc64918a31
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>
CppEditor: Check <include path>/QSomething

For the quick fix AddIncludeForUndefinedIdentifier, if no class is found
via the locator, check the "Qt include paths" for a header file with the
same name as the class name.

Task-number: QTCREATORBUG-9538
Change-Id: I13c86844c2ff653fa479dc91eb109af2a6d76fae
Reviewed-by: Lorenz Haas <lykurg@gmail.com>
Reviewed-by: hjk <hjk121@nokiamail.com>