Merge pull request #4 from cordawyn/activemodelish

Activemodelish stuff
Update README and add Travis-CI hooks.
Set version to 0.4.0.
Remove 1.8 versions from .travis.yml
Remove Gemfile.lock from repo, and ignore.
Minor yard updates, and include redcarpet in gemspec.
Don't install redcarpet with JRuby.
Use source https://rubygems.org in Gemfile.
Merge branch 'ruby-rdf-master' into activemodelish

Conflicts:
	Gemfile.lock