Nltk-tgrep

Allow trailing semicolons in tgrep2 search strings.

Implemented labeled nodes and segmented patterns (7).

Implements new features: comments, macros, multiple patterns, case insensitive node names (issues 5, 6, 9). Also includes a few more test cases.

Bugfixes to issues 2 3 4 8.

- treat bytes and str the same in py3

- better setuptools for py2
- fix bug for py2.6