QtConcurrent limits resource usage to a global number of simultaneous
threads. That means that if some QtConcurrent based algorithm currently
grabs all threads, any other use of QtConcurrent blocks, which is not
what we want.
Use the new threading methods of C++11 instead, but still use
QFuture(Interface) manually for status reporting.

Task-number: QTCREATORBUG-14640
Change-Id: I8fecb43b5235da92c0d239e7dd5f2c108ab32ebf
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>