Correctly format commons links with spaces

Spaces should be replaced with underscores in URLs, underscores should be
replaced with spaces for link texts, plus signs should stay what they are.

Using Title here is probably not completely sane since it takes the local
configuration into account. It works, though.

Bug: 61738
Bug: 45046
Change-Id: I4cac81188e5a09bd1a4cbf5ccdf3c579fce9821a
Merge "Correctly format commons links with spaces"