use spaces for indentation (change tabs to spaces)?

[petri]

By convention, spaces are nowadays used, see PEP8: https://www.python.org/dev/peps/pep-0008/ - but not at the expense of consistency.

[jnj16180340]

Causes problems in python 3.5

=============================================================== ERRORS ================================================================
______________________________________________ ERROR collecting tests/test_cleanname.py _______________________________________________
.eggs/pytest-3.0.7-py3.5.egg/_pytest/python.py:418: in _importtestmodule
    mod = self.fspath.pyimport(ensuresyspath=importmode)
.eggs/py-1.4.33-py3.5.egg/py/_path/local.py:662: in pyimport
    __import__(modname)
<frozen importlib._bootstrap>:969: in _find_and_load
    ???
<frozen importlib._bootstrap>:958: in _find_and_load_unlocked
    ???
<frozen importlib._bootstrap>:664: in _load_unlocked
    ???
<frozen importlib._bootstrap>:634: in _load_backward_compatible
    ???
.eggs/pytest-3.0.7-py3.5.egg/_pytest/assertion/rewrite.py:216: in load_module
    py.builtin.exec_(co, mod.__dict__)
tests/test_cleanname.py:3: in <module>
    from cleanco import cleanco
E     File "/home/nate/BioBright/cleanco/cleanco.py", line 77
E       loname = name.lower()
E                           ^
E   TabError: inconsistent use of tabs and spaces in indentation
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Interrupted: 1 errors during collection !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
======================================================= 1 error in 0.10 seconds =======================================================

[petri]

done as part of the 2.0 work