DOC: fix spacing, add explicit diagrams credits
DOC: Tweak CSS for code listing.
TEST: minor spacing change
BUGFIX: CRFFD topologies support, fix #28
DOC: add CRFFD to the supported topologies.
TEST: fix test references, enable tests, minor changes.
Merge branch 'master' of https://github.com/ggventurini/python-deltasigma into tests
TEST: move tests for realizeNTF() to the new location.
Fix spacing in _nabsH.py.
TEST: move tests for realizeNTF_ct() to the new test folder.
TEST: move tests for PlotExampleSpectrum() to the new test folder.