- use a Register() method to register describers, instead of directly   setting on a map - allow the host, rev to be overridden by the user
- use a Register() method to register describers, instead of directly
  setting on a map
- allow the host, rev to be overridden by the user

gale320/embd,pctj101/embd,dboyliao/embd,ryancox/embd,kidoman/embd,dboyliao/embd,gavincabbage/embd,gale320/embd,pctj101/embd,gavincabbage/embd,kidoman/embd,ryancox/embd