Don't change global compiler flags when FFmpeg is enabled

It should no be longer needed. If it causes the issues please let me know
to find a more cleaner solution.
Fix T42326 trim operator not cancelled by the escape key.
Fix sequencer duplicate with only handle selected
Fix sequencer clipboard with meta's containing ID references
UI Icons: add 'triangle-bar' left/right/up/down icons.
BLI_listbase: add `BLI_swaplinks` which swaps given links' positions in given list.

Can be much simpler and quicker than using remlink/insert functions.
ShapeKeys: rework 'move skey' code, and add options to move to first/last position.

Main moving logic is moved to new `BKE_keyblock_move()`, which makes it available from anywhere.
In addition, move code was reworked so that it only loops once on whole keyblocks list,
and it accepts arbitrary org and dest indices, not only neighbor ones.

Partly based on work by revzin (Grigory Revzin) in his soc-2014-shapekey GSoC branch, thanks!
Fix tgz script, addons_contrib was in release
ListBase: use BLI_listbase_ for new api calls
Fix T42178: Cycles Film Exposure not triggering Viewport update
Fix T42257: Curve vertex parent not working with animation

Vertex parent was using original non-modified nurbs list, simply because
it didn't have something else to operate with.

Now we've got deformed by pre-tessellation modifiers nurbs in the curve
cache which might be used y the vertex parent.
Simplify GLSL in bump mapping, use gl_NormalMatrix where appropriate.
tangents are directions and should be transformed like directions.
Fix T42324: Curve deform modifier from mesh edge doesnt work properly

Curve parent requires valid path to exist for curve. If the path is disabled in
the curve settings, displist evaluation will check the dependency graph whether
the path is needed for parenting.

The issue was that changing relations in the scene chagned need of the curve path
but nothing tagged the curve to update it's path.

For now use direct call of DAG_id_tag_update from set_parent(). In the bright
future we might detect such a need in flush automatically in the depsgraph.
Fix T42278: Grease Pencil in Movie Clip Editor can not be erased in Track > Cursor mode

Eraser was not aware of possible transform matrix for the strokes.
Fix T42260: By repeatedly joining meshes, you could end up with thousands of UVLayers

This is only an indirect fix, in fact: this commit adds a public API to check
the maximum number of a given layer type (`CustomData_layertype_layers_max()`),
and uses it to forbid too much layer creation in `CustomData_merge()`.

This only affects UVs/VCol data though, but merge behavior in itself is not a bug
actually, how user managed to get thousands of different UV layer names remain
rather mysterious...
Linux/scons: fix compile, BF_BOOST_LIB_STATIC string was miising a space
Cleanup: style
Fix T42334: x-mirror fails in armature with a partially mirrored chain.

When resetting edit bones on cancel, they also have to reset connected
parent and child bone tips and heads respectively, since these can be
modified during the transform.
Cleanup: avoid loop-in-loop when mirror isn't used

Also name 'children' is normally used for a list
OSX: fix T42325 by not letting .vob handled by qt, avoids a doublefree