Bootstrap fix by Niels
Fix
Merge pull request #268 from egbertbouman/fix

Bootstrap fix
call_on_reactor_thread shouldn't be blocking
Merge pull request #269 from whirm/twisted-callback

call_on_reactor_thread shouldn't be blocking
_pending_tasks creation should be in the constructor
The behaviour change in call_on_reactor_thread broke all the tests.
Implement a new decorator with the old behaviour and use it on the tests.
Merge pull request #270 from whirm/twisted-callback

_pending_tasks creation should be in the constructor