Depend on the newest version of mite.rb

mite.rb has recently been updated to work with ActiveResource 3.1
Merge branch 'ruby1.9'
Get rid of Rubygems deprecation warning

> The source :rubygems is deprecated because HTTP requests are insecure.
> Please change your source to 'https://rubygems.org' if possible, or 'http://rubygems.org' if not.
Merge branch 'rubygems_source'