OSX: Hard-code -stdlib=libc++ for now

Required for C++11 support
Work around the 0-sized content item in Qt <= 5.2.

This causes an empty preview, since our shader effect source follows the
size of the content item. This is fixed in Qt 5.3, where the content item
has a properly updating size.
Fix setting arguments when invoking non-slot methods.
Also allow to emit signals in the methods tab.
fix initialization order warning
make sure to include graphviz/types.h after QString to avoid possible
conflicting declarations of string.h stuff, like memcmp() and strcmp()
Merge branch '2.1'

Conflicts:
	core/tools/objectinspector/methodsextension.cpp
use the compiler option -std=c++0x conditionally
rename 'set' variable and do some minor coding style cleanup
Support displaying of QQmlListProperties.

Requires a small extension of the VariantHandler, as QQmlListProperty is a
template class, so we cannot have a static list of all of them built in.
Move some code from the object model to Utils.

We need that in other models like the signal history one.
Improved QMetaMethod display, includes argument names and return type now.

Requires some extension on the method model though to prevent the return
types from messing up alphabetical sorting.
Display QMatrix4x4, needed in the QQ2 scene graph browser for example.
Introduce signal monitor tool

This tool provides an interactive of QObject signals. It's still work in
progress, some major features still need to be implemented:

  - display of time marks in the event view
  - print signal names as tooltips and in the graph if sufficient space
    is available
  - interactive range selection
  - timestamp rubberband
  - ...

SignalHistoryModel::Item also might need cleanup.
Improve colors in the signal monitor and restore selection
Remove debugging left-overs
Show tooltips for signal history
Don't show horizontal scrollbar for event view

Let's not show it by accident. We have our own, custom one.
Optimize layout compution for the event history
Use better formula to find event tooltips