Fix T41343, hard to remove group from objects.

Added a small menu with a few helper oerators next to each group panel:

* Remove group from all objects
* Select objects in group

More could be added possibly in the future.

Thanks to Campbell for the advice here.
Cleanup: mostly move together main area init/draw/handler callback, and some generic cleanup (tabs, comments...).
Fix T41323: Sequencer: video window taking all the place when switching to split view.

Issue is that, when we switch from full preview view to combined view, preview area has
its `sizey` set to use all available height, which leaves nothing for poor main area.

For now, make checks when switching mode to combined one, so that both areas have
resonable `sizey` values. Not perfect, but works.
UI: move button to set dupli-offset into group menu
Fix T41047: Text objects flipping
GHash/EdgeHash: avoid NULL check on iterator init
BMesh: use existing lookup tables when remapping
Comments
change scons default to be visual studio 2013
Experimental gooseberry request:

Expose radial control properties. That way, the operator can be tweaked
in the input preferences to tweak other properties as well.
Cleanup: Remove special code for Visual Studio 2008.

Goodbye VC2008, it has been a pleasure (more or less) :D SCons / CMake cleaenup will follow.
Differential Revision: https://developer.blender.org/D715
Fix T41333: Selected mask points don't stand out visually.

Looks like mask points coloring was recently changed, and IMAGE space colors were left uninitialized...
Factorized a bit the code about vertex_handle & co too, was quite duplicated.
Fix crash on dyntopo when show diffuse option + collapse is used

Some nodes could end up without any faces and in that case getting a
face material would fail.
T41354, cursor never gets reactivated in uv sculpting.
Add blender launcher application when building with MSVC

Main idea of this change is to make a small executable which
will set OMP_WAIT_POLICY environment variable and then will
launch blender itself.

This is a teporary solution for the time being we'll have a
more clear solution to high CPU usage with OpenMP when building
with MSVC.

Reviewers: campbellbarton, juicyfruit

Reviewed By: juicyfruit

Differential Revision: https://developer.blender.org/D717
Cleanup: unused defines
Fix for mathutils.Euler on big endian systems

D719 from jrestemeier with edits
Tweaks to the recent wrapper on windows

- Forgot to handle command line arguments

- Because of the fact we need to be able to
  use stdout and stderr we need to use regular
  console application for the wrapper.

- Because of using regular application for the
  wrapper we need to check forparent PID in the
  isStartedFromCommandPrompt().

I really hope it's not gonna to become any more
complicated.