add crossfilter ref; closes #113
add mapmakers-cheatsheet; closes #102
relocate some scraping pip installs

Not really sure what they were doing hanging out in the geo resources.
add scrapy tutorial link; closes #60
add Hue in map-reduce resources; closes #57
add link to Harvard slides; closes #38
add py viz notebook; closes #33
add link to metis; closes #114
add LA open data; closes #62
Merge pull request #126 from ajschumacher/more_links

a bunch more links; close moar issues