Merge bug fixes from qtjambi upstream

[kkofler]

As far as I can tell (from checking the history of the old qtjambi5 repository at https://gitorious.org/qt-jambi/qtjambi5?p=qt-jambi:qtjambi5.git;a=shortlog), the qtjambi5 code was forked from qtjambi around the new year 2013. There have been several fixes and improvements to the upstream code since then:
https://github.com/qtjambi/qtjambi/commits/master
(up to September 2015 when the project apparently died) and, as far as I can tell, they were unfortunately never merged into qtjambi5. It would be useful to merge these changes.

In particular, I am missing my fixes to cppimplgenerator.cpp:

• qtjambi/qtjambi@4824795
• qtjambi/qtjambi@84efb6b

(I checked that the changes are indeed missing.)

Upstream also added test cases for my changes:

• qtjambi/qtjambi@2f249fa
• qtjambi/qtjambi@3a15a37