* deduplicates URL generating/parsing code
* gets rid of spaces in URLs
* fixes error for file names with / in them (in case they exist;
current MediaWiki seems to disallow such names anyway)
Change-Id: I5aad43f6af1b99523c597c39befcc9db1ecab83a
Mingle: https://wikimedia.mingle.thoughtworks.com/projects/multimedia/cards/371
With apologies to anyone who gets a hundred merge conflicts
because of this :)
We had several different prefix styles (mlb-, mw-mlb-, mw-mmv-,
mw-mmv-mmv-, a few unprefixed), which was getting annoying,
and will be confusing to wiki editors who are trying to figure out
where a given style comes from. Such changes are better done before
going live because it breaks all local CSS tweaks on the wiki,
so I am renaming things now (also removing some stuff which wasnt
used anywhere).
Change-Id: I00447a25f0028e234169c6db941bedc99622eb8d