Merge pull request #100 from e3c/master

Fix corrupt initial frames https://github.com/wang-bin/QtAV/issues/70
fix decode error if a frame should be decoded multiple times

ffplay continue instead of break
fix crash if flush a decoder not open
fix crash when open/close decoder is called.

open and close codec with ffmpeg api is not thread safe unless we enable
lock manager. av_find_stream_info will call open. shall we enable lock
mgr?
fix a potential crash

don't know why it happens
fix dylib search issue on mac. reorder rpath to avoid depend lib version conflict.

for linux, executable_path > executable_path/lib
for mac, execautable_path/PlugIns
TODO: ios, android
player: use opengl by default if opengl in Qt is enabled
remove dead code. the can keep in 1.2 branch
player: online tv list widget
player: translation. lager toolbar size
more renderer related controls in VideoOutputEventFilter
misc