MAINT: fix a few test failures and style issues in tests.
MAINT: fix a few test failures and style issues in tests.

Also test all modes of idwtn.

ThomasA/pywt,aaren/pywt,rgommers/pywt,rgommers/pywt,eriol/pywt,eriol/pywt,ThomasA/pywt,kwohlfahrt/pywt,eriol/pywt,aaren/pywt,PyWavelets/pywt,aaren/pywt,grlee77/pywt,kwohlfahrt/pywt,PyWavelets/pywt,michelp/pywt,grlee77/pywt,michelp/pywt,michelp/pywt,rgommers/pywt,kwohlfahrt/pywt,ThomasA/pywt,rgommers/pywt