Remove reference to grokengine-default.xml config file, not relevant to NuPIC,
reverting 24b16d61594b5125471bd6eb061b089abdaf19c7 in the process.  Fix
super() calls in py/nupic/support/configuration_custom.py
Merge pull request #31 from oxtopus/grokengine_configuration

Remove reference to grokengine-default.xml config file, not relevant to ...
Fixed example OPF command on README.md; referenced unset environment variable $NUPIC_HOME
Merge pull request #35 from dbrody/updated-README-OPF-link

Fixed example OPF command on README.md; referenced unset environment variable $NUPIC_HOME
Merge pull request #38 from scottpurdy/master

Adds env.sh to install