allow value 0 for duration

Add flexible methods

Improve travis config

Correct the getText() method of the Message entity

- Include PHP nightly build
- Keep composer packages cached for faster testing
- Uniform indentation (2 spaces)
- Let travis manage composer updates (don't self-update)

Correct the getText() method of the Message entity to correctly return the text, with and without the command.

various

inline query command fixed

Small optimization

Fix cancel command if no database is connected.

Using getUpdates needs a valid database connection.

Add inline line breaks in logs.

Fixes #127

Update Request.php

See https://github.com/akalongman/php-telegram-bot/pull/228

Introduce Guzzle

Thanks! 👍