Updated pigs.eel and added two optimized versions

Added fps display and average fps printout to pigs.eel, removed
the pigs[i] caching alltogether, and cleaned up the psneudo-random
number generator a bit.

Added pigs2.eel, which caches pigs[i] in the main loop body.
(That was there all along; I just forgot to use it after the
BlitSurface() call...)

Added pigs3.eel, which uses vectors instead of tables for the
pig objects, to avoid the hash (binary search) lookups.

Added pigs2.eel and pigs3.eel to test.eel.