Extract body heights

Create a method to determine the height of a body based on its highest
and lowest x coordinate value, where the lowest is at the origin
(Assumes fixed rotation)

Use method to extract height of standing and ducking bodies, which
should be consistent for all variants

[[Warning: Method untested]]
Create option to switch body from the top

If fromTop is set to true, bodies will treat the top left corner as an
origin when switching, rather than the bottom left.

Body switching from the top is implemented where the legs disappear upon
taking flight. This is so that the legs go up into the body, rather than
the body moving down suddenly (causing a jerky flight).

[[WARNING: Untested!]]
Merge branch 'develop' of https://github.com/SweatyReptile/loser.git into develop
Fix failing body switch

switchBody() was passing oldBody into setTransform(), where it should
have been passing in newBody