Fix T39597: Missing entries in VSE Preview menu

This adds some view ratios in the video sequencer menu, based (copied) on the UV/Image Editor. It also fixes the inverted ratio issue reported in the same task.

Reviewers: #video_sequencer, #user_interface, schlaile

Reviewed By: schlaile

CC: jta, dingto, sergey, schlaile

Differential Revision: https://developer.blender.org/D447

== libredcode / licence cleanup ==

Changed libredcode to GNU GPL v2 or later to make it more compatible
with additional libraries added to blender.

== FFMPEG / Canon DSLR footage workaround ==

The latest ffmpeg versions include a workaround to deal with a certain
pecularity in Canon DSLR footage: instead of decoding pictures with the
proper resolution of 1920x1080 they decode it with 1920x1088 and add a
black bar at the bottom.

Needless to say, that this screws up things in a lot of areas within blender
(proxy indices, mask animations etc.)

Since all blender versions besides Linux x86 32bit seem still to include
older ffmpeg versions which still contain this bug, this patch adds
a workaround for older versions until we have all versions on all platforms
up to date.

See also: http://git.libav.org/?p=libav.git;a=commit;h=30f515091c323da59c0f1b533703dedca2f4b95d

== Sequencer ==

This fixes the placement code of new files added to the sequencer timeline.

The old code tried to guess the strip position from the current mouse
pointer position.

Annoying effect: if you add a new strip using the menu, especially if the
file editor pops up, the strip ends up in nowheres land (most likely around
track 40, frame -200).

New behaviour: strips are always placed at cfra, which is the
sequencer equivalent to the 3D cursor (and that's where new objects in
3D editing end up).

Bonus feature: we try our best to guess the right track by finding the
nearest strip by type.

The patch was inspired by
[#32766] VSE: Add Strip on Current Frame

Thanks to venomgfx for the idea!

== Sequencer ==

Made my last fix a little bit faster and more elegant by not playing around
with seq->tmp (only reseting it to NULL, like the old code).

== Sequencer ==

This fixes a bug in sequencer cut tool:

* if you cut two strips of the same name class (MVI_XXXX.MOV and MVI_XXXX.001)
the two new generated strips will end up with the same name.
(easy test case: add a MOV file with it's accompanying audio track to the
timeline and then cut both strips at once into two pieces)

* visible problem: your animation data will get messed up on the way, since
the animation system doesn't know, which strip it should assign the
animation.

Problem was caused by generating a new list of sequences within the
cut_seq_list() function:

Since dupli_seq() can't see the members of the new list of sequences, it
won't be able to assign unique names in all cases.

[#34013] [video sequence editor] Offset and crop of strips are wrong

Applied patch by jehan after confirming the issue.

Thanks for the patch!

== FFMPEG ==

This fixes a memory leak caused by the last packet on stream EOF not freed.
(Memory leak occurs on ffmpeg heap managed by av_malloc / av_free, so it is
invisible to Blender)

Also: clean up the code a little bit (anim->next_packet was never really used,
so could be moved into a local variable)

== FFMPEG ==

This fixes [#32399] VSE doesn't show last 3 frames of Quicktime movie.

Some decoders store frames internally until EOF.
So one has to feed the decoding engine with empty packets after EOF
until all frames could be extracted properly.

== Inpaint Node ==

Fixed several small (stupid) issues with the inpaint node:

* on pixel order building, some ranges got wrong and origin was considered
several times.

* the convolution kernel didn't consider all pixels (+1,0),(-1,0),(0,1) and (0-1)
were omited, leading to suboptimal results (sometimes even black areas)

* alpha channel is now only affected an areas considered by inpaint.
That's only important, if you choose low iteration counts.