Fix redirect detection for HTTPS -> HTTPS redirect loops

Fixes http://cdt.org & closes issue #289

Signed-off-by: Nick Semenkovich <semenko@alum.mit.edu>
Merge pull request #295 from semenko/fix-redirect-bug

Fix redirect detection for HTTPS -> HTTPS redirect loops
Merge branch 'master' into rulesetUpdating
Prefix function call with this
Check the release type of the extension to make sure only ruleset releases appropriate to the extension are downloaded
Use Char type to properly access preferences
Check the version of the ruleset release, branch type, and database format version in one place before updating