Feature request: middle mouse support

Hi,

I was thinking to play Icewind Dale or similar crpgs on my tablet using only touch controls. The problem is when you have to touch at the edge of the screen to move on the map. On tablets this is a pain in the @$$ because sometimes you have to touch the upper edge and the android status bar will pop up.

So, it would be nice to implement an option to change the function of the "tap and hold in the same place to start a drag" (on Windows is the click and hold the left mouse button which draws a green rectangle on the screen) with the "grab the map and move it in any direction" (its the click and hold the middle mouse button and move it). The native android port of this game is functioning exactly this way.

A lot of crpgs and rts games will be possible to play in future.

No files, tests, or entry points are named. Start by locating the Android touch-input handling for map dragging and compare the requested behavior with the native Android port; done means an option supports middle-button-style grab-and-move without requiring edge touches.