Add definition of mpd class and a few basic methods for conversing with the mpd server.
Define a basic macro for generating commands to interact with the mpd server.
The following commands are made available:
    - play
    - pause
    - stop
    - next
    - previous
    - clearerror
These are commands that do not require parameters.
Add call to method that sends a close command to the MPD server.
Add docstring to 'send' method.
Modify defcommand macro signature.
Add defcommand1 macro and update defcommand implementation.
Add playback options command definition.
Add a few mpd query commands.
Add playback control commands.
Add commands for manipulating connection settings.
Add command for listing audio outputs and a couple of commands for client to client communication.
Add cl-mpd system definition.
Merge branch 'master' of github.com:lucastadeu/cl-mpd
Remove license file.
Substitute call to |close| method for a simple call to the 'send' method.