BS-4.7.4
Add what's new for 4.7.4 and update proguard
Improve Simplified Chinese translations.
Closes issue #484 : back-port almost all the orientaiton logic from BS+ to handle reverse-mounted cameras on devices like the Nexus 5X
Ignore a few more Android files
Target API 22 since not yet updated for new permission model; fix beep problem that surfaces in Android 6; update plugins
Work around enum + proguard + dex problem