Improved password validation and fixed some VCCS problems. Is not
finished yet.
Merge remote-tracking branch 'origin/master' into change_password_form

Conflicts:
	eduiddashboard/views/password.py
Refactored password change views.
Added the first file for doing the tests. Now it's not working because
a problem in vccs_client API. Also refactored a little the vccs module
to make it more testeable.
Better name for the test class.
Merge remote-tracking branch 'origin/master' into change_password_form
Adapting the password tests to the new URLs.
We have to use the same factor salt for checking passwords. Also we
ensure of removing revoked credentials.
Define password input types for the passwords widgets.
Implemented tests for password change form.
Used a mock VCCS client to make tests work without connection to the
VCCS server.