Add links to subprojects to readme
Add links to subprojects to readme

It's always a pain trying to navigate between all the different API Umbrella projects, so I propose we add links to them all straight from the master project.
apinf/api-umbrella,NREL/api-umbrella,NREL/api-umbrella,apinf/api-umbrella,apinf/api-umbrella,apinf/api-umbrella,NREL/api-umbrella,apinf/api-umbrella,NREL/api-umbrella