Switch to DeviceDetector 2.X

* Switched to DeviceDetector 2.X
* Do detection only once (in tracker/settings). There is no need doing device type detection in DeviceDetection plugin as all those detections are already done before (Doing them twice slows down tracking)
* Introduce new DeviceDetectorCache to use an optimal caching for DeviceDetector (File Cache + Static Caching)
* Speed up detection for bulk requests (thx to @cbonte)
* Use special parsers where only those are needed (e.g. check for bots or mobile os)
could be a `const` ?