Changes needed to support Django 1.10

  - Added Django 1.10 to travis CI
  - added a "fake" option_list attribute to BaseBowerCommand
    so accesing this code elewhere won't break (doesn't exist in Dj 1.10)
  - Added support for the new add_arguemnts api for management commands,
    it seems the two APIs can coexist fine.
  - Changed travis config so it prints stderr to console and uses tee to send copy to file `test_out`