use sre to process regexes properly to remove capturing groups
Update internals.py

It might be a good idea to make the distinction between capturing and non-capturing groups since technically, they are all grouping parentheses. I've only changed the docstring for this function slightly but maybe the function name shld be updated accordingly if others have this confusion in the future.
use pip requirements file directly as a pip argument
Merge branch 'pull_request.stanford_tokenizer' into pull_request.stanford_jenkins

Conflicts:
	nltk/parse/stanford.py
download nltk stanford dependencies
allow directory paths for environment variables in find_jar_iter()
move external dependencies to the 'third' directory
added environment variables to the stanford parser & tokenizers
added stanford environment variables to tox
added stanford parser doctests
Merge branch 'pull_request.stanford_jenkins' of https://github.com/jskda/nltk into develop
fix to https://github.com/nltk/nltk/issues/545, renamed convert_regexp_to_nongrouping() to compile_regexp_to_nongrouping() as there isn't an official python module to stringify a parsed regex
Merge branch 'develop' into pull_request.regex_remove_groups

Conflicts:
	nltk/internals.py
fixed some bugs in convert_regexp_to_nongrouping_parsed()
raise ValueError when there are backrefs in regexes
Merge pull request #574 from jskda/pull_request.regex_remove_groups

Regex remove groups bug
Merge pull request #567 from ltiao/patch-1

Update internals.py
renamed non-grouping to non-capturing (for regexp parentheses), cf https://github.com/nltk/nltk/pull/567
merging https://github.com/nltk/nltk/pull/567