Call testcaseDone after failed assertion

[Naktibalda]

This change makes Mocha finish testcase immediately after failed assertion.
Jasmine had no such issue and is not affected by this change (output stays the same).

Please tell me if there are any side effects caused by not calling calling failCb.

Fixes #14

[codeforequity-at]

I recognize the problem, but I think this is not a good solution, as it makes testmybot less portable for other testing frameworks (and jasmine adapter requires some changes too).
I think the better way to solve this would be here.
have to give some thought about the mocha vs jasmine differences here - while jasmine has a global "fail" function, mocha handels test cases failure with a test case specific callback.

[Naktibalda]

I don't see a way to call done callback in failCb.
Relevant discussions: chaijs/chai#586 mochajs/mocha#1128

[codeforequity-at]

Solved with latest commit! Thanks for your input!