Desired accuracy and loggin

Hi,

I added [check against redefining AKLLog value](https://github.com/romaonthego/AKLocationManager/commit/496cd3141d545db11836f49fba53854339f432de) (it's useful if you don't want to receive AKLLog messages in console, so you can disable it in Prefix.pch file) and ability to [set desiredAccuracy value](https://github.com/romaonthego/AKLocationManager/commit/1dbf960f689516cd51c504c3a5a3c93f7ce04cef).

Please merge and update the podspec.

Thank you!