Change notes: Enabling and disabling of menu items

I did a complete rebuild of the code that keeps items in the menus enabled or disabled based on whether you're logged in and whether or not the file in the current tab is read-only. This was a good thing to do at this point because it led to a careful review of the menu commands and the commands in the icon bar. #

There's still more work to do here. It should have some of the functionality of the arrow pad. For example it should disable Expand if the bar cursor headline is already expanded. And Move up should be disabled when the cursor is on the first item at its level. #

Thank you to Anton, one of the best testers I've worked with. He uses the software vigorously, understands its "virtuality" (a Ted Nelson term) and expects the software to implement his (correct) understanding the world it defines. This part of the software was unfinished, and buggy. #

In the voicemail (see below) I talk about that idea specifically -- it's a kind of innocence and naivete that it is totally worth preserving. Most software doesn't live up to that promise. But rather than turn the user into a cynic, I want the software to be where he is. Why should it permit a user to do something that makes no sense? That doesn't serve to reinforce the virtuality. #

BTW, this only applies to File, Outliner, Reorg and Tools. The other menus either don't need them (the commands always work, e.g. Docs), or are user-defined, so it's not practical for Drummer to manage them. I could do something with the Bookmarks menu because there are two commands in that menu that Drummer controls. #