Changes

Use CanonicalOverwrite for StarMixins#getNeighboursRecursive

As an added bonus, this approach is backwards-compatible with
older versions of SLL (although it won't overwrite the original
galimulator method, thus yielding worse performance for these
lookups and will even cause crashes [stack overflow] when they
are called with rather large arguments - this for example
happens when populating religions while generating very
large galaxies).
 (commit: 8dd8fd3)