bug in chat80 doctest
fixed name error in compile_regexp_to_noncapturing(), cf https://github.com/nltk/nltk/issues/580
removed doctest from compile_regexp_to_noncapturing as it doesn't work anymore
fixes unit testing bugs for https://github.com/nltk/nltk/issues/581
removed now unnecessary calls to sorted()
added back unittest & sorted, see comments: https://github.com/nltk/nltk/pull/583
added the 'flags' argument to sre_compile.compile()
Merge pull request #583 from jskda/pull_request.581

fixes unit testing bugs for https://github.com/nltk/nltk/issues/581
Merge pull request #582 from jskda/pull_request.regexp_noncapturing

Pull request.regexp noncapturing
fixed syntax errors in stanford parser doctest
removed non-existent import
Merge pull request #584 from jskda/pull_request.tokenize_doctest_bug

nltk tokenize doctest non-existent import
skip test if the stanford parser jar doesn't exist
formatting
raise the correct errors in nltk.internals
fixed bugs in first doctest
Merge pull request #585 from jskda/pull_request.579

Pull request.579
fixed bugs in stanford tokenizer doctests; skip doctests if the jar doesn't exist
moved setup_module to bottom of code, see kmike's comments here: https://github.com/nltk/nltk/pull/587/files#r9105156
changed docstrings to raw docstrings for better readability