repopick: let's be nice to our servers :)

* Prefer fetching changes from GitHub, and if that fails,
  silently fall-back to Gerrit.

Change-Id: Ibf68d4b69a7e8dbee2adb8f7f4250340b8be629c
repopick: remove the superfluous information from date

  * '2011-11-17 06:54:52.000000000' -> '2011-11-17 06:54:52'

Change-Id: I73d37c9aba13d4be6b4d2d2fc0f2f83971a3e77b
repopick: gracefully handle empty/non-JSON server responses

Change-Id: Idbabdbfb4a910de0ad405f02b2a84cf2bc9ef3dc

Conflicts:
	tools/repopick.py
build: get rid of the sparse expand stuff

* i don't see a reason why we are doing this because we never deal
with flashing system img rawly
* This will put useless write on ssd..
* we don't have space on ssd

Change-Id: Icd53d161b8515f5eca238b98ad68515d69caa34f
envsetup.sh: add missing dquotes

Change-Id: Ic86a5dd36b0f32cd7dc4d2f9c187566398796ed6
releasetools: use prebuilt boot image if using a custom boot image makefile

Change-Id: Ic348d31e8df7933dc4f9f055b7a5a2beacc21d32
lets make the lunch list look a little neater

It's very simple, but with more and more devices coming in, a long list won't cut it
There are probably better ways of doing this, feel free to comment

Change-Id: I9bd1fef920f985a133c882df9987b6be29dbc7b8