Demand-load most modules in the commands and ui modules.
# HG changeset patch
# User Bryan O'Sullivan <bos@serpentine.com>
# Node ID 059c6e42fc4221816e26a72bef8cf780891989ca
# Parent d2994b5298fb20f87dc1d4747635b280db3c0526
Demand-load most modules in the commands and ui modules.
This improves response times for a number of simple commands, as the
Python interpreter doesn't end up loading modules that it never uses.
There's less benefit to demand-loading in other modules.