wishlist: retain timestamps on asset files copied to output

[maphew]

it would be nice if the time stamps on the static asset files were retained when copied to the output directory.

This would make it easier to update the remote web host later, enabling "only copy new files" without (having to) resort to checksum and/or file size matching.

[posativ]

I add "hardlink to output if possible" to the wishlist :)