Spacewar: beam weapon hit detection problem

```
It seems that when the beam travels at 45 degrees angle, it passes through
stationary ships without impact.
```

Original issue reported on code.google.com by `akarn...@gmail.com` on 11 Apr 2012 at 7:00

The issue names no files, tests, or entry points. Start by reproducing a beam fired at a 45-degree angle against a stationary ship, then trace the beam hit-detection path. Done means the beam registers an impact on stationary ships at that angle and existing collision behavior remains intact.

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