Fix QtCore version detection on Mac.

There might still be cases missing, but at least the framework scenario
works properly now.
Add static properties for a few networking classes

This permits inspection of TCP/IP sockets, I/O devices
and socket notifiers.
Static network properties: Build fixes for Qt4
Link with QtNetwork on Qt4
Apparently the Qt5 build also needs QtNetwork
Minor: Remove tabs from CMakeLists.txt
Merge remote-tracking branch 'origin/1.3'

Conflicts:
	core/CMakeLists.txt