Merge remote-tracking branch 'origin/master' into chenyan

Conflicts:
	res/layout/frag_music_item.xml
	res/layout/frag_video_item.xml
	res/values/strings.xml
	src/com/chainton/pdmclient/adapters/FragMusicAdapter.java
	src/com/chainton/pdmclient/fragments/MusicFragment.java
	src/com/chainton/pdmclient/fragments/PictureFragment.java
	src/com/chainton/pdmclient/fragments/VideoFragment.java
	src/com/chainton/pdmclient/system/service/GalleryMusicService.java
	src/com/chainton/pdmclient/system/service/GalleryPictureService.java
	src/com/chainton/pdmclient/system/service/GalleryVideoService.java
	src/com/chainton/pdmclient/system/service/SystemMediaService.java
Merge branch 'master' into chende

Conflicts:
	res/values/strings.xml
修改选择状态下切换页面的downloadItem