Raspberrylink

Features
- Support for configurable auto-reconnect cache file location in raspberrylink-server.conf.

Bug fixes:
- Fix crash on startup when /var/cache/raspberrylink-last-device exists but is empty
- Fix OpenRC init script (had wrong executable path for starting the server)

Changes compared to the previous 1.*
- Consolidated code: got rid of separate audio and server processes, combined into one
- No more redundant communication between UNIX sockets
- Reduced usage of shell commands in python code
- Use DBus much more now for bluetooth-related functions
- Less polling: listen for DBus signals
- **Full support for track information, media play/pause/back/skip over REST API**
- Functional call-support (according to my testing)

Notable Changes:
* Attempts to autoconnect to last known device on startup

- Try to connect to the audio service socket multiple times before failing
- Fixes raspberrylink-server service from failing to start since the audio service takes a few seconds to start up and have the socket binded.

- Set BlueZ agent to run using python3, fixes a dependency error as well (agent would crash and pairing wouldn't work)
- Include python-gobject in dependencies
- Try to improve voice call routing (still not stable)