restrict, a first update command

There will be hundreds of query and update commands, so the AgileWiki framework has been organized to minimize the code needed to write these commands. But today it occurred to me that I didn't have any sample update commands. So I wrote one, restrict, which sets/clears the Restrict classifier entry. As well as being a sample, it helped me debug the framework. (And working code is always easier to understand, yes?)

I've also reorganized things. Commands are now in one of three packages under AgileWiki.framework: apps, queries and updates.

Tomorrow maybe I'll work on the scripting portal.

Bill