add "./sync-all fetch" and "./sync-all new"

add "./sync-all fetch" and "./sync-all new"

./sync-all fetch

  Fetches remote changes from the "origin" for each sub-repo.  Useful
  before "./sync-all new".

  (Runs 'git fetch origin' on all sub-repos.)

./sync-all new

  Lists the new patches relative to "origin" for each sub-repo.
  You probably want to './sync-all fetch' first.

  (Runs 'git log origin..' on all sub-repos)