Added objects for pre-trained models

This commit includes four companion objects that are initialized
with the models pre-trained on the Microsoft Research Asia, Academia
Sinica, Peiking University and City University of Hong Kong corpuses
Merge pull request #121 from oskarsinger/master

Added objects for pre-trained models
Added F1 score method and tweaked punct recognizer
Added mains to trained objects for testing
Converted Mention to CorefMention
Changed all instances of Mention to CorefMention
Made CorefMention extend from Phrase as Mention did
Confirmed forward coref scores were not impacted by change
Deleted 2 trained objects and cleaned

Deleted the PKU and AS companion objects due to low F1 scores
and cleaned up the rest of the code a little
Merge pull request #123 from oskarsinger/master

Cleaned up some bad/unnecessary stuff
Found and fixed error for document annotation test
Removed Mention Class
Moved Entity from Mention class to CorefMention class
TODO:
      Implement WithinDocEntity and remove Entity string class
Merge branch 'master' of https://github.com/factorie/factorie
Added Ceafe metric and average back in