fix zip in tests/test_frame.py

fix zip addition issue in io/stata

fix zip issue in tests/test_groupby
CLN: Unicode --> six.text_type
CLN: unicode --> six.text_type
CLN: basestring --> six.string_types

CLN: Use py3compat's StringIO

Py2/3 StringIO usage

basestring fixup

StringIO fixups
try fixing io/stata
CLN: Use reduce from six.moves
cleanup instance checks in pandas/tests, add assert_isinstance method

and also pandas/tseries/tests, pandas/stats/tests
CLN: stats/tests, sparse/tests - use relative imports

relative import in rpy

CLN: relative imports, instance checks in pandas/io
CLN: Python 2/3 compatible sort in ez_setup
change 1 to True in doc
TST/ENH: Add assert_isinstance util to util/testing
CLN: Modernize pandas/tests + better type checks

Use assert_isinstance + replace type(a) == b with assert_isinstance.
Some 2/3 fixes of .sort() --> sorted

Better instance tests in io/tests

CLN: assert_(isinstance --> assert_isinstace

CLN: better instance checks in scripts/

CLN: better type check in perf_HEAD
CLN: 2/3 fixes to util/decorators
CLN: Use compatible long in io/stata
CLN: Cleanup type checks in core/config

Make is_instance_factory cleaner + basestring --> (str, bytes)

fixup for wrong isinstance change
add in some missing imports for six and tm

Fix import / cruft from fixes
CLN/ENH: Fixup to iteritems in util/compat

CLN: more .iteritems() --> compat.iteritems

Left doc with six.iteritems.
use list(range in pytables tests

last range fixes
CLN: modernize compat + remove cruft
Fix thread imports for Python 3

add missing six import to io/stata

thread's get_ident only needed in 2.6