Added self as a field variable in init and removed self vars from functions
Added seekTo function that seeks to a specific offset in the media
Use the callback in connect if present
Fixed reconnect issue. If stop was called, connect would subsequently fail
Rolled back commit which added self as field variable.

It seemed to introduce some issues on re-use of the same device over several re-connects, so let's just stick with the extra few lines of code.
Close existing connection if one is open when connecting
Fixed setVolume and added setVolumeMuted call.

SetVolume was relying on an old way to set volume in castv2-client, see https://github.com/thibauts/node-castv2-client/commit/c01c7c40b01c02c8cfdff7bcb6443ef42ecb42de
Added device.close call to close the underlying castv2 connection
Updated test to include testing of new calls and fixed it up a bit
Added test for device re-use and re-connect
Updated castv2-client version to 0.0.8. This is needed for setVolume and setVolumeMuted
Fixed client not being properly closed
Merge pull request #9 from ddaf/master

12 commits from @ddaf improving a lot of stuff :)