Revert date filter changes from 313edd5edd376ca12b773285a261086138120f20.
Revert date filter changes from 313edd5edd376ca12b773285a261086138120f20.

I don't mind the unix epoch features as such. But they belong in
another filter module, as it's not a feature of Django.

truqu/erlydtl,chaptastic/erlydtl,chaptastic/erlydtl,wrw/erlydtl,aerosol/erlydtl,A40in/erlydtl,quasiconvex/erlydtl,erlydtl/erlydtl,chaptastic/erlydtl,project-fifo/erlydtl,project-fifo/erlydtl,wrw/erlydtl,huangered/erlydtl,wrw/erlydtl,erlydtl/erlydtl,oxpa/erlydtl,quasiconvex/erlydtl,oxpa/erlydtl,alexr/erlydtl,quasiconvex/erlydtl,campanja-forks/erlydtl,campanja-forks/erlydtl,alexr/erlydtl,huangered/erlydtl,kivra/erlydtl,aerosol/erlydtl,erlydtl/erlydtl,project-fifo/erlydtl,campanja-forks/erlydtl,A40in/erlydtl,kivra/erlydtl,aerosol/erlydtl,A40in/erlydtl,huangered/erlydtl,kivra/erlydtl,truqu/erlydtl,truqu/erlydtl,alexr/erlydtl,oxpa/erlydtl