added read-write of states
removed PhraseTable from PhrasePair
added redability feature models
added scripts for tuning
Fixed word penalty bug affecting certain platforms.
Disabled reference tracking on phrase and phrase pair flyweights.
Merge branch 'master' of https://github.com/chardmeier/docent
Fixed flyweight serialisation templates.
Merge branch 'master' of https://github.com/chardmeier/docent into aaron