make course listsings (front page) opaque keys compliant
make course listsings (front page) opaque keys compliant

jbassen/edx-platform,jbassen/edx-platform,caesar2164/edx-platform,Stanford-Online/edx-platform,jbassen/edx-platform,Stanford-Online/edx-platform,caesar2164/edx-platform,jbassen/edx-platform,caesar2164/edx-platform,jbassen/edx-platform,Stanford-Online/edx-platform,Stanford-Online/edx-platform,caesar2164/edx-platform