Bug 6934: Fix code in CashRegisterStats (dataTables pagination, more accurate descrip...

Bug 6934: Fix code in CashRegisterStats (dataTables pagination, more accurate descriptions, add a delimiter pull down, change C4::Dates to Koha::DateUtils)

I cleaned up the code according to comment #23. I got rid of DHTMLcalendar_dateformat,
beacause it wasn't use in cash_register_stats.tt. C4::Dates is deprecated,
Koha::DateUtils is now used.
Some column names are changed and the pagination for the dataTables is fixed.

Signed-off-by: Hector Castro <hector.hecaxmmx@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>