convenience functions for strictmath

[pshaughn]

playset game logic shouldn't trust javascript math in many cases, and should generally restrict themselves to integers (power-of-2-denominators are okay but harder to verify). playsets.js needs a utility object to provide some useful integer-domain operations, truncing the input when passed a non-integer

• trunc
• mod (with non-negative output)
• floor(sqrt(x)) (so we won't ever be calling Math.sqrt from directly inside playset code)
• integer approximations of sin(x)256 and cos(x)256, with x in integer degrees (the 256 is of course arbitrary, but some choice must be made and stuck with!)
• integer degree approximation of atan2 (this doesn't have to always return the closest integer to the exact correct result, as long as it's close, it gets the 8-way cardinals right, and it has all the appropriate symmetries about the 8-way cardinals) It might not be a bad idea to actually overwrite the not-guaranteed-deterministic Math methods on the client, so playsets that try to use them will fail to. On the other hand, client-only UI calls are allowed to be nondeterministic and might want them!

[pshaughn]

geometry tests should go in here too, as games need them (an asteroids game with some exact triangle collisions seems like a good thing to do)

[pshaughn]

in progress (no atan2 or geometry tests yet)

[pshaughn]

added methods to iterate an object by ascending numeric keys (barely math, but it does involve numbers)