Add missile reflection

[clintbellanger]

Allow the creation of missile powers that reflect when hitting a wall, instead of dissipating. Look for a good spot (maybe the MapCollision class?) to calculate reflection angle.

For fun, try adding a Block-based power that reflects enemy missiles back at the enemy. This could be a very fun power for melee builds vs. pesky ranged creatures.

[igorko]

Migrated to clintbellanger/flare-engine#78