Added checks for expanded template files to the sdist command.
Added checks for expanded template files to the sdist command.

Before producing a source dist package, the command makes sure that
the expanded template files and compiled Cython files are present
and up-to-date. This prevents from shipping outdated files.

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