Avoid opening multiple PhotoErrorDialog
Remove photo quality setting: There're too may problems to solve
Drop support for Android 3.x (Now only support for API >14)
Fix MainDrawerActivity: header view should be added before adapter is set
Fix ImageSearchPhotoFragment: Crash when show key is invalid/expired
0.4.0 released
Merge branch 'release/0.4.0'

Conflicts:
	README.md
	ehreader/build.gradle
Update README.md
merge 0.4