Added statistical numbers (new, lapsed, upgraded..) to Repeat Report

Adds statistical numbers:

% New Donors
% Lapsed Donors
% Upgraded Donors
% Downgraded Donors
% Maintained Donors

+ information about Date Range Two.

There are a few things worth mentioning that I see as potential
concerns.

1. I think there may be a better way to display the "Date Range
One:" and "Date Range Two:" titles that appear with the statistics
listed at the bottom. The way I did it works, but may not be the
preferred way.

2. The "New Donors" percentage is calculated based on the donor
not giving in date range one (rather than ever). I saw that this is
how the label "New Donor" in the far right column was being
calculated, so stuck with it for consistency, ease, and to avoid
having to make a separate and potentially-expensive sql query.

3. The report (before and after my changes) depends on the date
range being chosen for date range one being chronologically before
the date range chosen for date range two. I noticed that the far
right "% Change" column also depended on this, so I didn't do
anything to change it. Perhaps just renaming the selects in the
Report Criteria --to clarify that date range one should come
first-- would be an acceptable solution to this.