No bug - Remove bogus gen path. r=me
Bug 889749 - Expand the TLS ciphersuite offered for Android background services.

This adds the intersection of the Android 4.0 ciphersuite (determined
by enumerating several device's offered ciphersuites) and the
intersection of Brian Smith's proposed
ciphersuite (https://briansmith.org/browser-ciphersuites-01.html) and
orders them by Brian Smith's ordering.
Bug 892025 - Pre: add HKDF.derive helper.
Bug 892025 - Pre: Add BaseResource.post(JSONObject).
Bug 892025 - Pre: Fix Utils.byte2Hex(b, length).

I muddled this merging mcomella's byte2hex -> byte2Hex rename.
Bug 892025 - Part 1: Add SRP constants.
Bug 892025 - Part 2: Implement FxAccountClient.