this -> self (so javascript. many this. wOw)
Updated register token

Fixes #353
Fixes #341
also send read receipt
Fixes: "AttributeError: 'ReaderThread' object has no attribute 'sendPong'"
Merge remote-tracking branch 'origin/read-receipt'
Merge remote-tracking branch 'waalt/js-fix'
https://github.com/waalt/yowsup/commit/4374727d28f4c8c60e6aa671131925e9dac743fb