differentiate back navigation from safari page load
 
Fixes #130

see also:
http://stackoverflow.com/questions/10756893/how-to-ignore-popstate-initial-load-working-with-pjax
add console logging for debugging
Merge pull request #131 from codeforamerica/fixes/130-continuous-reloading

Fix issue #130 continuous reloading
Merge pull request #5 from codeforamerica/master

Merging fix for continuous iOS page reloads from cfa/master.