Add sorting to multiple post display about fireblog HOT 2 CLOSED

Whilst working on this, I have made it so that the tag view page, by default, displays the newest post first. Previously, the sorting was oldest post first. Making this change brings both view_all_posts and tag_view together in having the same behaviour.

from fireblog.

I have found and corrected a very subtle bug in some of the tests. Essentially, I was doing something like range(5, 10, -1) instead of range(10, 5, -1). As I was iterating over this (essentially), I ended up iterating over nothing resulting in the tests silently passing.
And if that wasn't enough, the numbers passed to range were also incorrect, and took some time to correct.

from fireblog.