Use ReportingPeriod to select / eliminate campaign finance information

[bcipolli]

See https://github.com/caciviclab/caciviclab.github.io/wiki/Campaign-Finance for details. Depends on ReportingPeriod data needed from #221.

[bcipolli]

Because we have the netfile xaction ID and a treasurer-reported ID, it's possible that we can simply skip reloading rows (rather than delete them), or modify/update them (in case $$ amount changed, or simply to report that the data were pulled from form 460A instead of 497, for example).

So, this could wind up being trivial.

[bcipolli]

This is actually non-trivial. Chatted with @andrell81 , have some good ideas on how to get this done.

[mikeubell]

We have gotten rid of the reporting period information so this is obsolete.