Remove constraints on lateral movement

While rewriting the physics code, I apparently managed to eliminate
swarmers much earlier than I hoped. :) I was assuming that removing
swarmers would have required an entirely new physics engine, to avoid
creatures with a small head that barely moves, and a big tail that
oscillates wildly. Actually, the problem with swarmers seemed to be
related to the way I managed angles. Creatures still have an
"impossible" angle setup (the "tail wiggling the dog" effect), but this
doesn't seem to be a huge problem. I can probably live with it.
Inline sproutOrgan() methods in Organ
Synchronize a couple of Organ methods
Attempt at using fast precalculated sin and cos tables
Change caching strategy to avoid deadlocks
Remove synchronization from trigonometric tables to make them faster
Remove useless synchronization from Narjillo
Update backlog
Remove trigonometric tables
Minor refactorings
Remove fast sin and cos tables

They did improve speed, but the minimal improvement (5-10%) simply
wasn't worth worrying about the lack in precision. The lack in precision
did have an effect, judging from the very different results of
experiments. It's hard to tell whether it was worse or simply different,
but I decided not to take the risk and simply revert to Java's standard
Math.sin() and Math.cos(). I'll consider re-adding fast trigonometric
tables in the future, if the next iterations of the physics engine
happen to do a lot of trigonometry.
Fix tests
Misc refactorings
Restructure movement code

To make it understandable to humans such as myself
More deep refactoring and fix rotation bug

This is a biggie. Apparently, the forces were calculated based on a
relative center of mass, not the absolute one. As a result, rotation was
completely b0rked. Now that I fixed this, all the creatures' rotational
movements appear much more natural. Next step is applying some real
physics to calculate rotations instead of the current ad-hoc code.