Restore using sheet-style dialogs on OS X 10.8+.
Fix ColorPicker tooltip to be multi-line wrapped.

Also, fix icon when the system theme on Linux does not have a "color-
Update all translations for string changes.
Update build to use x264 HEAD and FFmpeg 2.2.
Ignore audio filters in MltXmlGpuChecker.
Update translations.
Make it easier to adjust image duration on timeline.

Previously, the duration of an image could not be stretched longer than
the image duration in Properties, which defaults to 4 seconds. It is not
always obvious or convenient to change image duration in Properties.
Instead, let image duration in Properties adjust the out point, and let
image duration be stretched up to 10 minutes in Source player or on
timeline.
Add Settings.savePath property and use it.
Improve appearance of mute and volume toggles on OS X system theme.
Workaround Stabilize filter crash at end of analysis on Windows.
Fix regression in commit da80be2 on Linux and Windows.
Convert webvfx filter to QML