Uses secure RubyGems URL
Merge pull request #1179 from pmcconnell/patch-1

Uses secure RubyGems URL
Removes some confusion from ContenTypeDetector methods
Fixes a test that caused an error in Ruby 2.0.0
https in the Gemfile.lock
add -layers 'optimize' flag to animated gif convert cmds
animated gif option formatting
fix tests from animated gif layers optimize change
Clarify tests for frame dimensions
Add ruby-2.0.0 to travis CI
Merge remote-tracking branch 'upstream/master'