Add repopick script from CM

patchset 4: cybojenix
  clean up the script:
    remove fetching from github
    cleaned up fetching locations of binaries
    if ANDROID_BUILD_TOP isn't defined, error out

PS 5:
  Added back the check if fetch succeeded.
  Fixed verbose print about fetching.

patchset 6:
  final changes
    fix detecting ANDROID_BUILD_TOP
    send all relavant data to stderr

Change-Id: If67c5f178d03fadd8b79b1908f4a9cb231efbb28
repopick: Add a way to checkout instead of cherrypick

This helps if you want to take a commit and its dependencies, and not
just a particular commit

Change-Id: Ib245cce560c7b0d6fd03198a8c69a13d4720a4cb
repopick: Allow picking batch of commits with the same Change-Id

Gerrit does allow assigning the same Change-Id for multiple commits. This patch allows picking them properly.

Change-Id: Idedc64f58eebe41a0d212c72329d15acff24efb9
repopick: Don't redirect stdout on --quiet

For some reason, when --quiet is specified (example:
repopick --quiet -c 7834), git ends up in /home instead
of the actual repository.

This is a quick workaround until a proper solution is found

Change-Id: I60e0f684909a23b557ee3147b8954b71be995319
Make repopick support gerrit 2.9

Change-Id: I5b5fcfdfb69fd8639a7170f68966817ba1bb98b7