[IMP] RegForm: Disabled inputs data is sent
[FIX] RegForm: Empty space on empty string
[FIX] RegForm: yesno field validation
[FIX] RegForm modify: keep previous value
[MIN] RegForm style tweaks
[IMP] RegForm non-billable sessions on priorities
[FIX] RegForm: textarea default size
[FIX] RegForm: Social events with 0 places