Bug 6934: QA Follow-up

Bug 6934: QA Follow-up

Tried to address every single thing that QA mentioned :
1)Removed isNull function
2)Changed datepicker properly
3)We have to fill in two dates not to be flooded with old entries if we don't want to.
4)The first two fieldsets are now in one bigger field set
5)Removed the use of $fullreportname variable
6)Removed the use of dt_from_string when it already recieved a DT.
7)Removed comments starting with "###" in cash_register_stats.pl
8)Used Text::CSV::Encoded to generate the CSV file (used guided_reports.pl as an example)
9)I am not sure if using C4::Reports::Guided is the right choice here. I instead used the same column names as the one recieved by the query in cash_register_stats because this report uses columns from 5 different tables in addition of using both firstname and surname twice.

For the ninth point, I would like to know more about C4::Reports::Guided if you still think using it would be a better solution. Thank you!

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>