Bump version to v1.3.0-rc1. Update React to v16.6
Bump version to v1.3.0-rc1. Update React to v16.6

hms-dbmi/higlass,hms-dbmi/4DN_matrix-viewer,hms-dbmi/higlass,hms-dbmi/higlass,hms-dbmi/4DN_matrix-viewer,hms-dbmi/higlass,hms-dbmi/4DN_matrix-viewer