flake8: ignore undefined name inspections in py33
flake8: ignore undefined name inspections in py33

- jsprettier/util.py:23:17: F821 undefined name 'unicode'
- jsprettier/util.py:24:26: F821 undefined name 'unicode'
- jsprettier/util.py:25:27: F821 undefined name 'long'

Reason: intended behavior for st2/py2-vs-st3/py3

jonlabelle/SublimeJsPrettier,jonlabelle/SublimeJsPrettier