Avg time scraper fix

Updates:
1.  Beautifulsoup replaces lxml [issues 245](https://github.com/18F/foia-hub/issues/245)
2.  Years no longer hardcoded, years not come from scraping the main data page for available years. [issue 246] (https://github.com/18F/foia-hub/issues/246)
3.  Attribute names now have no spaces or dashes [issue 244](https://github.com/18F/foia-hub/issues/244)
4.  Tests added
5.  In some instances rows had the value `<1` which were not being parsed correctly by lxml or Beautifulsoup, all these instances were changed to `1`, which fixed the alignment.
6.  Csv was updated to include all the data and the data no longer moves around with every run. 
7.  PEP8 formatting, for real this time. 
8. It turns out the foia.gov/data doesn't use all the same exact names as foia.gov/report-makerequest and there is no easy transformation. To fix this issue I had to make a mapping key.