Await for a Bridge to listen to its port

[jaller94]

Fixes #192

This allows for errors of .listen to bubble up and get handled.

[Half-Shot]

Seems reasonable

[jaller94]

I will need to return a Bluebird promise for our tests.
Also, this may have increased the time we have to wait beyond Jasmine's default timeout.

[Half-Shot]

How come? This shouldn't affect the tests?

[jaller94]

Some tests use returnValue.done() instead of .then() as the last handler, which only works if .run() returns a Bluebird-Promise, but not a native Promise.

[Half-Shot]

oh, fair enough then.