Add download thumbnail file function.
Merge remote-tracking branch 'origin/riversyang'

Conflicts:
	src/com/chainton/shareservice/app/fragment/AppFragment.java
	src/com/chainton/shareservice/app/fragment/ContactFragment.java
	src/com/chainton/shareservice/app/fragment/FileFragment.java
	src/com/chainton/shareservice/app/fragment/MusicFragment.java
	src/com/chainton/shareservice/app/fragment/PictureFragment.java
	src/com/chainton/shareservice/app/fragment/VideoFragment.java