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()