Implement more tests for rules

[andersfischernielsen]

I've encountered players being able to execute a lot of illegal moves (according to the real-world game rules).

We should cover the full ruleset in the Shared tests.

[andersfischernielsen]

Related to/identical to: #80

[andersfischernielsen]

#80 is a duplicate of this.

[andersfischernielsen]

All implemented features now have tests. On to implementing the remaining functionality, then

[andersfischernielsen]

points.spec.ts, harbors.spec.ts, and trading.spec.ts are the only files missing tests.

[andersfischernielsen]

trading.spec.ts now has tests (22b95f1)

Missing:

• points.spec.ts (tests for players gaining most knights and longest road are missing)
• harbors.spec.ts (all tests are missing)

[andersfischernielsen]

neighbouringHexCoords in MatrixCoordinate.ts currently makes all harbour tests fail, since it's reporting incorrect neighbour hexes.

[andersfischernielsen]

Tests have been added for harbors.spec.ts. Only a few tests in points.spec.ts are missing.