Added an immutable spanvarlist
Mutable SpanVarList is now called SpanVarBuffer
Added SubclassableVector
Moved Mention package to coref folder
Made Mention extend Noun Phrase
DOES NOT COMPILE - more edits need to be made for the immutable spanvarlist replacement
Moved MentionFinders for coreference from nlp.mention package to coref.mention package
Renamed ConllCorefLoader to LoadConll2011 and moved it to nlp.load package
Immutable SpanVarList and Mutable SpanVarBuffer
Updated files to use these types
Made Mention extend from phrase
	Previous code had duplicate methods, now have a semantic representation for a mention that can be a noun phrase or verb phrase
	phrase.NounPhraseGenderLabeler/phrase.NounPhraseNumberLabeler are now:
		GenderLabeler/NumberLabeler which take a type that extends phrase and a list that extends TokenSpanList

	Updated files that call these
Updated Files that called ConllCorefLoader to call LoadConll2011