Bug 919426 - Part 1: Add new file WifiCommand.jsm. r=vchang

WifiCommand.jsm is used to call the native C API and control wpa_supplicant
Bug 919426 - Part 2: Add new file WifiNetUtil.jsm. r=vchang

WifiNetUtil.jsm provides network related facilities.
Bug 919426 - Part 3: Make use of WifiCommand/WifiNetNet in WifiWorker.js. r=vchang
Bug 774521 - Desktop Web Runtime UI implementation for mozGetUserMedia (Camera API). r=myk
Bug 925620 - Turn on logging in geolocation tests. r=jdm