Pyatv

**Changes:**

* Add power interface
* Add device information interface
* Convert module (convert.py) is now public API

**Notes:**

* General improvements to protobuf handling (for developers)

**All changes:**


e4f6590 devinfo: Minor clean ups
d645d5a devinfo: Add device_info to atvremote
33622b8 devinfo: Get version from osvers
e3ad40b devinfo: Add documentation
df8f6a1 devinfo: Clean up zeroconf properties
908d2ea devinfo: Add support for device info
8da7fd2 devinfo: Add helpers for extracting device info
cb8d73a if: Add interface for device information
d8624fd MRP Power State support (458)
1f97630 if: Tidy up convert module and make it public
ce926b0 protobuf: Move pyatv imports in protobuf.py
554d965 gha: Trigger on both push and pull_request
a8ab245 gh: Run actions on pull requests
024284b mrp: Add some protobuf definitions for voice
ac3ae13 mrp: Wait for command responses
c765dbe mrp: Download protoc and verify generated code

1cd5508 Add initial text about concepts to documentation
5b51db5 Add badge to LGTM

**Changes:**

* Fixes position in MRP

**All changes:**


511e83e mrp: Fix calcuation of position
1ba1030 scan: Remove non-breaking space in names

**Changes:**

* Fix minor state bug and implement seeking in MRP

**All changes:**


9ab37c6 Change zeroconf warning to debug
3155e84 mrp: Fix device state handling

**Changes:**

* Added some missing DMAP tags
* Limit log print outs to not flood logs
* Minor updates to protobuf definitions

**All changes:**


5f46dac Consolidate protobuf scripts into one script
0cfb9fc Ignore some unknown DMAP tags
ad95943 Supress unknown DMAP media kind
413eb32 Add some missing DMAP tags
bfa5a45 New protobuf message and minor updates
8ee3183 Limit log printouts for binary data att protobuf

**Changes:**

* Fixed bug where device state would be reported as "paused"
when playing (yielding incorrect position as side-effect). This
also fixes delta updates, where metadata would sometimes be
lost.
* Fixed bug where a crash would occur if a device had a = (0x3D)
in its MAC-address
* Added artwork_id to metadata that gives a unique id for artwork
* Use cache for artwork that saves the latest four artworks
* Identifiers in config is now prioritized in order
MRP, DMAP and AirPlay
* AirPlay is not handled specially in config now. If no AirPlay
service is added, no service will be implicitly created.
* Error handling (raised exceptions) are now more consistent
when pairing

*Breaking changes*

* AirPlay interface has been renamed to "stream", e.g. use
atv.stream.play_url instead of atv.airplay.play_url.

**Notes:**

* Running tests on Windows works again
* This release contains a lot new test coverage and all "common"
functional tests have been ported to MRP
* Last documentation have been migrated to markdown
* Moved from travis to GitHub actions

**All changes:**


635ec68 Change last files from rst to markdown
cff609d Remove AirPlay as special case
63f230a Change AirPlay interface to Stream interface
d11fba1 Add priority to identifiers in config
17c685d Improve device state and delta updates in MRP
bcb69de Use content id as hash in MRP