* Initial implementation of Asterisk Mailbox

* Rework asterisk_mbox handler to avoid using the hass.data hash.  Fix requirements.

* Handle potential asterisk server disconnect.  bump asterisk_mbox requirement to 0.4.0

* Use async method for mp3 fetch from server

* Add http as dependency

* Minor log fix. try to force Travis to rebuild

* Updates based on review

* Fix error handling as per review

* Fix error handling as per review

* Refactor voicemail into mailbox component

* Hide mailbox component from front page

* Add demo for mailbox

* Add tests for mailbox

* Remove asterisk_mbox sensor and replace with a generic mailbox sensor

* Fix linting errors

* Remove mailbox sensor.  Remove demo.mp3.  Split entity from platform object.

* Update mailbox test

* Update mailbox test

* Use events to indicate state change rather than entity last-updated

* Make mailbox platform calls async.  Fix other review concerns

* Rewrite mailbox tests to live at root level and be async.  Fixmailbox dependency on http

* Only store number of messages not content in mailbox entity