Osx applescript

Hi Alex,

I've ported your linux server to OSX using a combination of applescript and native calls.  It passes most of the tests in test-client.py, with the exception of the batch command returning:
`jsonrpclib.jsonrpc.ProtocolError: (-32602, u'Invalid parameters.')`

My initial debugging attempt was
`(Pdb) p result
{u'jsonrpc': u'2.0', u'id': u'8foc6fgr', u'error': {u'message': u'Invalid parameters.', u'code': -32602}}`

I'd like to get feedback on this port and if you're amenable to merging this into your repo.

I'm also at a bit of a loss at the moment.  Do you have a short example to walkthrough using a grammer to drive a shell session or edit some text in an editor?

Thanks!
Ed