Put the ship damage overlay behind a lab so it can be easily
enabled/disabled. Over time, more features will be placed behind
labs as they're being developed or experimented with.
Add bomb tails behind a lab. The trail renders a bit strangely when
it's fired along the vertical axis.
Remove 'dotprod' from the namespace.
Create a constant, math.Vector.ZERO to represent the zero vector.
Use this shared constant instead of instantiating a new vector
object each time a zero vector is needed.
Remove @fileoverview and @author tags from top of each file.