test_transition

[lehins]

Great app, I was looking for something like it for a while. Thanks a whole bunch!
One small suggestion:
instead of returning True on
object.get_state_info().test_transition('transition_name', user)
it would probably better to return state_info instance, so the call can be chained:

try:
    object.get_state_info().test_transition('transition_name', user).make_transition('transition_name', user)
except States2Exception as e: 
    raise ValidationError("Cannot changes state because %s" % e) 

instead of:

try:
    if object.get_state_info().test_transition('transition_name', user):
        object.get_state_info().make_transition('transition_name', user)
except States2Exception as e: 
    raise ValidationError("Cannot changes state because %s" % e) 

This way it is type consistent (test_transition never returns False anyhow), it is more DRY and by chaining calls like that we could also eliminate failed transition logs in a more concise way.

I would submit a pull request myself, but it is literally a one line change:
from True to si_self in model_methods.
More over this change wouldn't break any existing code, since si_self would still evaluate to True.

What do you guys think?