Make old rapidsms pagination "digg-style" pagination

Show pages around current page in pagination.
Update paginator template to be use bootstrap
Don't show extra pages (border or adjacent) when there aren't items there.
Remove href tags from disabled links.
Fill in gaps of 1 page with missing page not elipsis.
Tests for paginator
Remove vim header
Fix set syntax for python <2.7
Disable Next button on last page.
Clean up variable names.  Remove now unused context variables.
Remove unused import
Paginator tag documentation
Merge 297-pagination. Fixes #297
Merge branch 'release-0.12.0' of https://github.com/rapidsms/rapidsms into release-0.12.0