Add Schedule B1 (Loan) fetching

This fetches data from Schedule B1 and tacks it onto the Contributions
table. (See #126 and #150)
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