Axisrewrite

This modification allows users to either choose to continue to do axis2dataref the same way, OR users can replace range= with drl= and drh=.

drl= is the value to set the dataref when the joystick axis is at 0%
drh= is the value to set the datared when the joystick is at 100%

This allows the user to choose arbitrary ranges (for example -4 to +10):
drl=-4
drh=10

or the user can reverse the action of an axis, (needed for throttles or cowl flaps on some planes) by specifiying the max dataref value on the minimum axis and the minimum dataref value on the max axis:

drl=1
drh=0