bug 832463: rename balrog-client.py (and associated bits) to balrog-submitter.py. r=rail

--HG--
rename : lib/python/balrog/client/__init__.py => lib/python/balrog/submitter/__init__.py
rename : lib/python/balrog/client/api.py => lib/python/balrog/submitter/api.py
rename : lib/python/balrog/client/cli.py => lib/python/balrog/submitter/cli.py