Maintain image transform tool
==================================
Add intermediate function to detect boundary edges that will be
artificially pinned and faces to reunwrap. Still not 100% certain the
reunwrap method will work, still I hope it will do the trick. Still, a
similar function will likely be needed for the second method that I will
use, should the first one fail.

Maintain image transform tool
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GUI and RNA options for retain image transform tool. This is known as
"preserve UVs" in other programs, but I find this terminology deceptive
because UVs are, in fact, modified. It is actually the image that is
maintained on the mesh.

Fix memory leak when trying to apply transformations to shared meshes

Don't link compositor with blender player.

Fix blenderplayr compilation

MinGW64 and possibly gcc 4.7 doesn't like interface as identifier.

Fix own mistake: Open Collada libs are different for MinGW/MinGW64

modal operation for bevel and inset:

This commit adds some first building blocks for the two operators to work modally based on mouse input. To make their function easier, two hotkeys are introduced, Ctrl+B for bevel and I for inset.

TODO:
After discussion with Campbell, we would like to add scale-style line indicators for the operators. This is already done for transform operators but a new interface for mesh operations may have to be written using pieces from that code since, strictly speaking bevel and inset are not exactly "transform" operators.

Also, a better input method for inset is needed and more options exposed. The method implemented right now uses mouse move for thickness and ctrl-mouse move for depth. These are calculated using the distance of the selection center in screen space and the mouse position. While that may work and prevents abrupt changes in values when switching from thickness tweak mode to depth tweak mode, it limits the magnitude of values that can be put into the tool especially in small or large scale.

Alternatives until a better method is written include:

* use relative offset (works but may give strange results)
* tweak manually after the operation.

Cleanup optimization compile flags for mingw-w64.
After testing it seems that for safe debug sessions, debug build optimizations need to be off.

Also removed sse flags from release flags since they are included in ray optimization flags which are on by default.

delete uv tools branch, it has been merged to trunk and edge mode support for stitch will need to be reworked for bmesh anyway, making a merge with trunk more or less impossible. There are also a few bugs with the code here that have been fixed in trunk