Update README with more instructions
Update README with more instructions

Signed-off-by: Alex Kofke <c196266af12125980d5e66676ed65acbc1f52c32@gmail.com>

ajschult/etomica,etomica/etomica,ajschult/etomica,etomica/etomica,etomica/etomica,ajschult/etomica