Add Schedule B1 (Loan) fetching

This fetches data from Schedule B1 and tacks it onto the Contributions
table. (See #126 and #150)
Merge pull request #158 from mikeubell/master

Restore change from 01f8f79 lost in 23dc0af6
Add counter for candidates' contributions to themselves
Show calculated self-contribution numbers on candidate page
Display the word "(Loan)" next to loans

It seems like we should do that at least...
Merge pull request #159 from tdooner/real_candidate_numbers

Real candidate numbers
Fix merge