extended NP patterns
add 'required for' patterns
avoid Prep pattern to allow string="to" at next level
allow RB before verb

also VB
multiple match
allow disjunctions
passive VG
allow VBG as JJ in NP contexts
add "by which" and "is a"
allow embedded patterns
add ditrans and attempt relative clause
allow possessive
Merge pull request #36 from allenai/grammar

Grammar
Merge branch 'master' into grammar

Conflicts:
	examples/chunks/noun.taggers
	examples/chunks/rel.taggers
	examples/chunks/verb.taggers