WIP: partially fix doctests

[matthew-brett]

See output of py.test --doctest-module.

Doctests were using double quotes when showing string output, but Python
uses single quotes for string reprs.

Still getting a very puzzling failure for the transliterate doctest:

___________________________________________________________ [doctest] inflection.transliterate ____________________________________________________________
Expected:
    u'alamolo'
Got:
    u'AlAmAlA'

/Users/mb312/dev_trees/inflection/inflection.py:384: DocTestFailure

The same bad output from the command line:

$ python -c "import inflection; print(inflection.transliterate(u'älämölö'))"
AlAmAlA

transliterate does seem to give the expected output from the IPython console:

In [1]: import inflection

In [2]: print(inflection.transliterate(u'älämölö'))
alamolo