Version bump to 0.3.0.
Changed Dictionary#encoding to return an Encoding object.

* Requires Ruby >= 1.9.1.
Ensure that Strings returned by Dictionary are in it's encoding.
Style.
Raise an ArgumentError instead.
Added specs for force_encoding.
Merge branch '0.3.0'
Fixed a typo in the gemspec.
Updated the gemspec.
Link to the README.