Remove executable bit from some files.
We don't need `a -> Vector Double` to be reversible; we can map `[[Vector Double]] -> [[a]]` for a known `[[a]]`.

This reverts commit cb84973277c9c1c36b089cc2b2c01e4b0c20f168.

Conflicts:
	src/Algorithms/Lloyd/Sequential.lhs
	src/Algorithms/Lloyd/Strategies.lhs
kmeans returns a Vector (Vector Point), rather than [Cluster]