Add new_chat_photo command

Fix minor mistakes

Feature/smartinterface

Add conversation tests and a few matching helpers.

Small cleanup fixes

Merge branch 'feature/smartinterface' of https://github.com/MBoretto/php-telegram-bot into feature/smartinterface

When the command ends, the last step should be to actually "stop" it, not before, as some data already goes lost when stopping the conversation.

reintroduced update()

Some typo corrections.

Since PHP 7 is officially out, make travis test it properly.