random -> numpy.random

[tcld]

Here the replacement of all uses of the random-module with respective numpy-methods.
Since this is kind of a break with save-compatibility and...everything, I guess, I also took the freedom to include some small changes so they aren't necessary in the future - I will add comments to the code to point them out and explain them.

Notes:

1. This is based on Make use of Numpy-Arrays #138 .
2. This does not pass the ancient-map tests (since that one uses RNG to determine its outcome)