python 3 support

[oplatek]

Problems CI:

ERROR: test_setup (pykaldi.decoders_test.TestPyGmmLatgenWrappeNotInit)

Traceback (most recent call last):
File "/home/travis/build/UFAL-DSG/pykaldi/src/pykaldi/pykaldi/decoders_test.py", line 39, in test_setup
self.assertFalse(self.d.setup(args))
File "decoders.pyx", line 95, in pykaldi.decoders.PyGmmLatgenWrapper.setup (pykaldi/decoders.cpp:2486)

TypeError: expected bytes, str found

FAIL: test_frame_in_assert (pykaldi.decoders_test.TestPyGmmLatgenWrappeNotInit)

Traceback (most recent call last):
File "/home/travis/build/UFAL-DSG/pykaldi/src/pykaldi/pykaldi/decoders_test.py", line 51, in test_frame_in_assert
self.d.frame_in(wav)
nose.proxy.AssertionError: AssertionError not raised
'AssertionError not raised' = <unittest.case._AssertRaisesContext object at 0x2ada9614a350>.test_case._formatMessage(<unittest.case._AssertRaisesContext object at 0x2ada9614a350>.'AssertionError not raised', 'AssertionError not raised')

raise <unittest.case._AssertRaisesContext object at 0x2ada9614a350>.test_case.failureException('AssertionError not raised')

FAIL: test_expand_prefix (pykaldi.utils_test.TestExpandPref)

Traceback (most recent call last):
File "/home/travis/build/UFAL-DSG/pykaldi/src/pykaldi/pykaldi/utils_test.py", line 53, in test_expand_prefix
self.assertTrue(gold['y'] == test['y'], 'prefix expansion fails')
nose.proxy.AssertionError: AssertionError: False is not true : prefix expansion fails
-------------------- >> begin captured stdout << ---------------------
{'prefixdir': b'myownpath', 'mypath': b'myownpath/origin', 'innerdic': {'a': b'myownpath/origin', 'b': [b'arg1', b'arg2']}, 'y': b'myownpath/origin/file', 'x': b'1', 'innerlist': [b'myownpath/origin/file2', b'arg3']}
test vs gold
{'prefixdir': 'myownpath', 'mypath': 'myownpath/origin', 'innerdic': {'a': 'myownpath/origin', 'b': ['arg1', 'arg2']}, 'y': 'myownpath/origin/file', 'x': '1', 'innerlist': ['myownpath/origin/file2', 'arg3']}
--------------------- >> end captured stdout << ----------------------
'False is not true : prefix expansion fails' = self._formatMessage('False is not true : prefix expansion fails', "%s is not true" % safe_repr(False))

raise self.failureException('False is not true : prefix expansion fails')

---

Ran 9 tests in 0.177s
FAILED (SKIP=1, errors=1, failures=2)