Update the student transfer command to transfer to multiple courses.

Quick cleanup

Making kwarg to suppress unenroll events.

pylint and pep8 errors cleaned up.

add commit on success.

Changing transactional behavior of the management command.
Merge pull request #5619 from edx/sanchez/transfer-student-command

Update the student transfer command to transfer to multiple courses.
Merge remote-tracking branch 'origin/release' into rc/2014-10-20