Gravity Perks - Limit Submissions 1.1.15

Added gpls_should_enforce_on_render filter to allow modifying when GPLS enforces feed limits on render.

Added new gpls_calendar_periods filter hook.

Fixed issue where Field Value rules with Hidden fields would be incorrectly enforced on render when conditional logic feed rules were not met.
Fixed a malformed MySQL query that could happen on initial render of a form when using Field Values rules set to multi-input fields such as Name fields.