Process deferred command additions in two phases.
Process deferred command additions in two phases.

Phase 1:

* Load external package commands
* => Add deferred external package commands$

Phase 2:

* Load plugin commands
* => Add deferred plugin commands

miya0001/wp-cli,2ndkauboy/wp-cli,aaemnnosttv/wp-cli,trepmal/wp-cli,GaryJones/wp-cli,gitlost/wp-cli,GaryJones/wp-cli,2ndkauboy/wp-cli,rodrigoprimo/wp-cli,rodrigoprimo/wp-cli,rodrigoprimo/wp-cli,aaemnnosttv/wp-cli,trepmal/wp-cli,aaemnnosttv/wp-cli,2ndkauboy/wp-cli,miya0001/wp-cli,gitlost/wp-cli,miya0001/wp-cli,GaryJones/wp-cli,trepmal/wp-cli,gitlost/wp-cli