Fix issue #122 (subcommand unload not recognized)
Merge pull request #123 from lulinqing/patch-1

Fix issue #122 (subcommand unload not recognized)
update patch module terminology

Try to be more consistent with the terminology.  In various places we
call it a "hotpatch module", "hot patch module", or "patch module".  How
about we just call it a "patch module" everywhere?