Removing pip requirements install step from INSTALL.md
Removing pip requirements install step from INSTALL.md


Former-commit-id: b758bffec1b8e6930d3561b568dce1055dc63a54
travs/PyOpenWorm,gsarma/PyOpenWorm,kaustubhcs/PyOpenWorm,openworm/PyOpenWorm,openworm/PyOpenWorm,hnunner/PyOpenWorm,gsarma/PyOpenWorm