Haystack removed a template context variable we used to grab the last

page number, for the "Last" page link in the paginator. This change

fixes that anchor.
It also fixes up the view code to use the modern version of range(),

to ensure consistency across Python 2.7 and 3.x.
Unit tests were added to ensure this doesn't regress in the future.

Verified that search results render and include all the right links

on Python 2.x and 3.x.
Unit tests passed.