nltk.tree.Tree.parse has apparently been removed/replaced by fromstring. There is bracket_parse too but it says don't use it.
Tweak so that ParsingShell should with newer and older NLTK.
Merge pull request #23 from jimwhite/BLLIP_MASTER

NLTK API tweakage.
first-stage/PARSE/parseIt.C: -N, -E help updates
first-stage/README.rst: Convert to RST, updated
first-stage/README.rst: Sections -> numbers
Also some minor tweaks.
first-stage/DATA/EN: remove old cruft
first-stage/TRAIN/README.rst: RSTified, updated
first-stage/PARSE/parseIt.C: Fix README path
README.rst: fix paths, Sparseval URL, citations