Add date operations

[drlrdsen]

I.e. for special price validations date operations would be critical. There should be something like: special_price_from is in the past (maybe at least X days?) and special_price_to is in the future (X days). Otherwise one cannot define whether the special price is still valid or not.

[boast]

+1

[Gugiman]

+1

[KingIsulgard]

+1

Also need this to check wether or not a product is new.

What's the current sitrep?