Instead of having two lists of paths, now only one list is used where
both include paths and framework paths can be mixed. This reflects the
way the compiler is invoked, and retains the (correct) search order.

Task-number: QTCREATORBUG-11599
Change-Id: I373953e3e305df5b7a0d10920e12d146584adf9f
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>