Update retry logic to avoid retries following long network timeouts; handle iOS 7 empty file URL host strings

git-svn-id: http://gtm-http-fetcher.googlecode.com/svn/trunk@131 b3aa69f0-f65c-a609-0a27-78855af037c1
Initial commit
Merge branch 'master' of github.com:pepperpop/gtm-http-fetcher