no more per-block http handlers (using globs now), delete works, mask works.

for a block to be able to receive a "quit" message, it needs to have the following code added to its for\select
```
                case <-b.QuitChan:
                        quit(b)
                        return
```
quit() closes all the channels for that block and should only be called after that block's inchan has been removed from every block that can send it messages.