simplification of bootstrap.py by using pip
simplification of bootstrap.py by using pip

hms-dbmi/fourfront,hms-dbmi/fourfront,4dn-dcic/fourfront,4dn-dcic/fourfront,4dn-dcic/fourfront,hms-dbmi/fourfront,4dn-dcic/fourfront,hms-dbmi/fourfront,hms-dbmi/fourfront