Bug 7679: Fix several bugs in circulation statistics wizard

Bug 7679: Fix several bugs in circulation statistics wizard

- Display values in NULL columns/rows
- Display columns/rows that contain values only in NULL rows/columns
- "To" filter in period row should be inclusive (YYYY-MM-DD should be
  YYYY-MM-DD 23:59:59)
- Make it possible to use only the "To" filter in period row (actually
  it results in DBI error (2 bind variables instead of 1))

Signed-off-by: Katrin Fischer  <katrin.fischer@bsz-bw.de>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>