Improve Wikipedia Loading Script
I wanted to flag a change from since we discussed this: I initially wrote a function for using the Wikimedia APIs to collect namespace aliases, but decided that adding in more http requests to the script wasn't a great idea so instead used that code to build a static list that I just added directly to the code.

Also, an FYI that python library dependencies weren't working on my local end so I wasn't able to directly test the code. I tested a copy with the problematic elements stripped (beam etc.) that worked fine, but someone with a working local copy may want to test just to make sure I didn't accidentally break anything. Also, while I would argue more strongly for some of the changes in this code, they are five distinct changes so not so hard to remove one or two if other folks think they aren't worth the overhead etc.
* More structured approach to detecting redirects
* Remove redundant template filter code (covered by strip_code)
* Add language-specific lists of additional media namespace aliases for filtering
* Add language-specific lists of category namespace aliases for new link text cleaning step
* Remove magic words (parser directions like __TOC__ that occasionally occur in text)

Fix #3400

With support from @albertvillanova 
CC @yjernite