FREE_FLIGHT mode with PAN and ZOOM for mobile

[mbalajee]

In our app we use Filament to render a BIM model. Users of BIM prefer FREE_FLIGHT mode along with PAN & ZOOM, to look inside the building, which the current free_flight mode doesn't offer. So I created FREE_FLIGHT_2 mode by copying code from FREE_FLIGHT & ORBIT mode (for PAN & ZOOM), no additional code added. Can I create a PR for this?

Result looks like this,

free_flight_2.mp4

Note: PAN doesn't work great, it takes the two finger gesture for Zoom instead of PAN. Have to tweak GestureDetector.java this has nothing to do with the new FREE_FLIGHT_2 mode

@pixelflinger @romainguy