fix #767: create a link from res/drawable-xhdpi/ic_reader_video_overlay.png to assets/ic_reader_video_overlay.png
add AppLogViewerActivity to zbetagroup preference.xml
Merge branch 'develop' into issue/767-re-enable-proguard
remove unused statement in build.gradle
Merge pull request #831 from wordpress-mobile/issue/767-re-enable-proguard

fix #767: re enable proguard