Clean up url creation for new posts

This does 2 things, hence 2 commits.

1) Cleans up some simple errors. Multiple spaces and trailing and leading whitespace.

2) This is a bit stylistic, but makes urls lowercase (to reduce the change of dupes) and changes spaces to underscores for better url creation.   If you don't want the lowercase, I could understand (and I can remove), but I think for small to mid-sized wikis it's a good thing to have.