Merge pull request #8 from s-mage/master

Speed it up again
Introduce the Tagger::Model#conditional method
Make the learning code less scary, again
Rewrite Tagger::Model#e using conditional
Bump version to 0.4.0.pre2
Update README.md [ci skip]
Ngrams#unigrams_count should be cached
Update gems
Enable Travis-CI on JRuby and Rubinius
Refine the Travis-CI configuration, again
Do it like the AMQP gem
Not sure why but this is reasonable
Decompose Viterbi algorithm even more