version 1.4.0

Changelog:
- Improve OpenGL: more pixel formats, supports QML(not stable),
    dynamic gl support etc.
- VAAPI: GLX direct rendering support. check 4k.
- DXVA: more decoding surfaces to improve performance
- VDA (OSX hardware decoding) support
- Android support. Easy to deploy
- Subtitle support, including QML
- Improve OpenAL. Works fine on most platforms including android
- FFmpeg libavfilter support
- Audio output api change
- deploy script for ifw, OSX
- Bug fix
- WIP: dsound, opensl, audio engine, audio filters etc.
fix av module install problem
gl: missing opacity uniform in GLWidgetRenderer
qml: playbackRate
qml: add meta data class like Qt.Multimedia
qml: meta data api
check AVFormatContext null when finding streams
use const ref in foreach
qml: default value for metadata. compare key lower case

if default value is set, e.g. title is QString(), then in
qml we can use title.length
qml: detect more meta data keys
qmlplayer: display meta data
qml: update qmltypes
va: no need to set va pixel format.

it will be set by ffmpeg after getFormat() is called. also
we can get correct original pixel format in Statistics
vda: use yuv420p. no nv12 for osx10.6
subtitle: issue280. rects > 1 at a given time
subtitle: unique supported suffixes
emit positionChanged if media stop pos is unknow

issue 289