Round crowdmatch calculations to nearest cent
Per design decision from @msiep (https://community.snowdrift.coop/t/crowdmatching-dollar-amounts-inaccurate/851/13)
We should round to the nearest cent for calculations that use dollar/cent values.
Right now, rounding is only done when displaying a patron's pending donation and monthly crowdmatches. This means that sometimes the monthly amounts don't sum to the total pending donation; this should never happen.
For example, my months sum to 69¢, but the pending donation is 71¢. Instead, the pending donation should be 69¢, or we should show the fractions of a cent in the monthly view. Which course of action we should take is being decided in a discourse discussion.