Fix T41219: Cycles backface detection doesn't work properly

Root of the issue goes back to the on-fly normals commit and the
latest fix for it wasn't actually correct. I've mixed two fixes
in there.

So the idea here goes back to storing negative scaled object flag
and flip runtime-calculated normal if this flag is set, which is
pretty much the same as the original fix for the issue from me.

The issue with motion blur wasn't caused by the rumtime normals
patch and it had issues before, because it already did runtime
normals calculation. Now made it so motion triangles takes the
negative scale flag into account.

This actually makes code more clean imo and avoids rather confusing
flipping code in mesh.cpp.
Image Editor: only do alpha test if output file requires alpha

(internal change, nothing should change to the user)
Bring back python operator for pies on a certain operator property.
Align pie menu title on center.
Correct missing new line in the debug print
Add custom property to previous commit, name "Context" of that property
was misleading.
Maybe slightly controversial pie commit:

Make pie menu item placement touch the radius from the internal side of
the buttons rather than placing on the center on the cirtcle. This
allows us to get rid of the separate visual angle property, also allows
for tighter placement of pies with a smaller radius without easily
overlapping.

Also pie menu title now always appears above the threshold indicator.
OSX: add a fix for lion_fs loosing handles after calling fs from key shortcut, also reenabled lion_fs for OSX >= 10.9 again
OSX: fix paranthesis in last commit
Fix T41408: Render layer pass bug, second attempt

Missed some passes in the previous commit. Now seems all the passes
are covered, at least with my understanding of the things.

There're some weird things going around with the refraction pass,
but that is caused by some other issue in the code. Would rather
call it a TODO for now.
Fix out of bounds read when recalculating mipmaps, error reported by
address sanitizer.

This was strangely only triggered when float buffers were used.
UI: edits to pie-menu-enum

- avoid eval
- report if operator is missing
remove MAXFLOAT define
hint checks to re-alloc as unlikely

also edit comments for knife tool
Fix T41431: Min/Max custom property range mismatch
Hack for edge-slide macro was lost in header cleanup

add back include for USE_LOOPSLIDE_HACK
BMesh: use a smaller dist3 threshold

Matches array modifier remove-doubles
Fix T41425: UI wobbles using scrollbar
Remove MSVC2008 workaround
Cycles: Correction to previous commit -- forgot to take instancing into account