Handle case sensitivity issues with pypi better
Handle case sensitivity issues with pypi better

The index is apparently case insensitive (or at least no one has uploaded two
packages whose names differ only by case as of the time of this writing), so
if the package name cannot be found, try to figure out the correct case for
it.

sandhujasmine/conda-build,ilastik/conda-build,ilastik/conda-build,frol/conda-build,dan-blanchard/conda-build,mwcraig/conda-build,rmcgibbo/conda-build,takluyver/conda-build,shastings517/conda-build,shastings517/conda-build,mwcraig/conda-build,sandhujasmine/conda-build,dan-blanchard/conda-build,takluyver/conda-build,rmcgibbo/conda-build,sandhujasmine/conda-build,shastings517/conda-build,rmcgibbo/conda-build,dan-blanchard/conda-build,frol/conda-build,ilastik/conda-build,frol/conda-build,takluyver/conda-build,mwcraig/conda-build