RevBy:    - hjk

Task:     - 234321
RevBy:    - Bjoern

RevBy: hjk

The code completion was keeping around references to old documents after
the completion finished. This caused documents to stay in memory when
unloading projects, up until the next time you used the completion.

ProjectExplorer::sessionManager -> ProjectExplorer::showSessionManager

Avoid creating a copy of the list of projects.

Conflicts:
	src/plugins/qt4projectmanager/qtversionmanager.cpp

Task:     -
RevBy:    -
AutoTest: -
Details:  Add the include path for qplatformdefs.h to the fot.

Task:     -
RevBy:    -
AutoTest: -
Details:  (Only outputs them via qDebug().)