Add sorting to multiple post display

[ismail-s]

• Get the views to work with a sorting parameter
• Update templates to display sorting select box and to handle changes to this box
  • Bootstrap
  • Polymer
  • Simple
• Test everything
  • Make sure default sorting is newest first
  • Make sure sort oldest first works
  • Make sure sort newest first works for page 2
  • Make sure sort oldest first works for page 2
  • Make sure sorting urls generated for both views are correct
  • Make sure templates work for both sorting orders (ie functional tests)

[ismail-s]

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.

[ismail-s]

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.