changing the "this" references to self in logging lib

The following code was failing when invoking the logging API with an error `Uncaught TypeError: Object [object global] has no method 'write' `

```js
var logging = kido.logging();

// just some helper methods to provide a 'nicer' api over the kido logging api
var log = {
    error: function (msg, data) {
        _log(logging.writeError, msg, data);
    },
    info: function (msg, data) {
        _log(logging.writeInfo, msg, data);
    }
}

var _log = function(handler, msg, data) {
    var logMsg = {
        msg: msg
    };
    if (data) logMsg['data'] = data;
    handler(logMsg).done(function (e) {
        console.log(e);
    });
};

```

We traced down the issue to the use of `this` inside the logging apis. These have been replaced with `self`. Please review and accept the patch.