some progress on mv

There will be two move commands, mvhere which moves the top-level topic under the browser-level topic, and mvthere which moves the browser-level topic under the top-level topic.

I'm working on mvhere first. Currently I'm working on the applicability rule. Its going slow.

On the other hand, I am keeping up with the laundry, shopping, cooking and dishes. And looking forward to Rupali's return.