REST Services Destroy Fix, Node Implementation

- `/destroy` now returns plain text in JSON format, just contains connectionID
 - `MpdConnection` now contains connectionID
 - Updated in `Regular.java` and `RESTServices.java`
 - Pushes request to Node
- `/getConnection` now returns the connectionID of each connection
- `/createConnection` now also works with node
This should still probably be a 500 error.
`return Response.status(500).entity(errors.toString()).build();`