Bug 906096 - Move InputMethod API behind a pref instead of build option. r=kanru, r=sicking

--HG--
rename : b2g/components/Keyboard.jsm => dom/inputmethod/Keyboard.jsm
rename : b2g/components/MozKeyboard.js => dom/inputmethod/MozKeyboard.js
Bug 914931 - Test packaged apps update. r=fabrice
Bug 917544 - Don't remember audio-capturing permission in a session. r=fabrice
Bug 919051 - Media Recording - memory leak when record a media stream without any tracks. r=roc, r=jsmith
Bug 919469 - Change the default value of the dom.webapps.firstRunWithSIM preference. r=fabrice