Runtime enablement of WebGL

Add Labs setting for enabling and disabling WebGL. Need to make sure
WebGL has been compiled in before showing runtime enablement settings in
Labs menu. Requesting information from the native side through JNI.

(cherry-picked commit from a2f7564cd95da42fad70e3c54497df7e7e8b1ea9)

Change-Id: Ie11bfa69941c2d75cfec04132908e07391c602fd
Added missing hungarian translation

Change-Id: Ieabd270d7413a456e19f42a529be578a88984f87
Deleting pref_video_preload_choices translations

Change-Id: I11e5826d2ff04dd40137f8b82bd16e922f4c42a0
Apply CLUSTER UI
UI Updated