Bug 799734 - Pre: Export browserid directory to mozilla-central.
Bug 799734 - Pre: Add Utils.byte2hex(byte[], int) and Utils.hex2byte(String, int).
Bug 799734 - Part 1: Add HTTP client for verifying BrowserID assertions.
Bug 799734 - Part 2: Implement generating BrowserID certificates and assertions.
Bug 799734 - Implement generating BrowserID certificates and assertions. r=rnewman