relax nokogiri version specification to ~> 1.6.0
allow activesupport 3.x or 4.x
fix Dor::Config.fedora deprecation warning under ruby 2.x
remove unnecessary sul-gems source
update geo2mods test cases
lock addressable to 2.3.5 to workaround frozen Addressable::URI runtime errors
Merge pull request #4 from sul-dlss/develop-fixes

Tests passing now