New browser engine reports based on new browser engine detection of DeviceDetector

*First step of removing old UserSettings stuff (refs #3962)*

- updates DeviceDetector to latest version (and adds missing browser/os icons)
- old BrowserType reports (UserSettings plugin) has been removed / replaced with new browser engine reports in DeviceDetection plugin
- those reports will be much more accurate as before the detection was only based on a browser name > browser engine mapping
- browser eninge is now stored in a new db field
- browser engine is also available for segmentation
BC for API is of utmost importance until PIwik 3.0.0 :+1: (for this we likely even keep BC after 3.0.0 since so many people will use UserSettings API).

Maybe the easiest would be to define an alias in this function which was implemented for it: https://github.com/piwik/piwik/blob/master/core/API/Request.php#L140-142