Qt4: speedup pictureflow rendering littlebit by using scanline and qtransform instead of doing those by hand

add a comment at the intention of the translators to tell them they can
use fancy Unicode characters
since this comment is UTF-8, add --from-code=UTF-8 option to xgettext

Use a macro to make DrawHelp() lines shorter
Merge 'Boxes' with 'Global' help category

It includes only .luac files

Workaround v4l2 drivers that do not behave correctly while enumerating inputs, standard, tuner, or format.

Crop/AR settings can now be changed by the video filters.
Crop/AR changes done by the decoder are now applied to the exact
picture and without any picture loss (before this patch, it was applied
too soon and due to the recreation of the vout display, some pictures where
lost).

They were previously lost.

Moved up two functions.

Now vout_SetDisplayCrop() takes crop parameters relative to the visible part.

The old code used the current thread affinity.

It is more of a workaround, a cleaner way to configure video filters
will need to be done.

The variables are void, not boolean.

We want compilation to fail if this is missing.

This reverts commit 884eaa35.