Fix T38637: Boolean produces faces with holes which isn't supported by BMesh

Simple fix -- use CarveHoleResolver hook for CSG which will split faces
containing holes.
Possible fix for T38644: H.264 with PNG RGBA encoding crashes
Fix T38667: When using "Maya" Input Interface, pressing "E" does not initiate rotation in the UV/Image Editor

Was a shortcut conflict with unwrap. Use 'U' for unwrap now, so no conflict is here.

Preset still doesn't work tho, Cambo need to solve missing operators used here since
NDOF changes.
Fix T38672: Can't select strips inside a Meta on the Mask Modifier
Fix regression that Blender crashes on startup if UI translation is enabled, it was mistake in rB50b2c78ad8b6.
Fix T38506: Bokeh blur node - size bugs with OpenCL.

The underlying cause for these issues is the insufficient sampling of
the bokeh image. For smaller blur radius there will be very few samples
taken, and with 1-pixel radius it boils down to just 4 samples:
2 on the left border (black), 1 in the center (black) and 1 at the top
border (blue) ...

For now have added the workarounds implemented in the CPU version of
that node, which hide these artifacts. Ultimately would be better to
have mipmap levels for the bokeh image input instead.
NDOF: Fix for fly/walk mode ignoring axis invert options
Fix T38698: In the Mask tab the Insert Key and Clear Key button labels are switched
Python: remove redundant len() use
fix - T38561: Fly mode vs. Walk Mode Navigation Keyboard Controls

* QE as up/down to Fly Navigator
* Alt as slow modifier to Fly Navigator
* Update on Walk header info

Note: I left the original RF/Ctrl shortcuts working for fly navigator
but they are no longer visible in the header info. So old users will
still be using what they were used to, while new ones get used to what
walk navigation is using.