Added support for options hash

Support for jQuery-style syntax:

    atomic.get('someUrl', {
       error       : function(){ console.log('error'  , arguments) },
       success     : function(){ console.log('success', arguments) },
       contentType : 'application/json;charset=UTF8'
    });

The following can be set via options:

* success
* error
* url
* contentType
* data