Tidy up "firewall_schedule_edit.php"

ID statements (DIV tags) cannot take a space separated list of words, so
use the underscore character between the month and year.

Make the ID statement in the TABLE tags unique by adding the month and
year PHP variables to the ID

At the end of the month, the TR tag is not being closed, so add a check
to see if the day count is greater than the number of days
Merge pull request #597 from ExolonDX/branch_01

Tidy up "firewall_schedule_edit.php"