[hobbit] New enable/disable tool ready for testing

[Tom Georgoulias]

Henrik Stoerner wrote:

> The host selection listbox lets you select multiple hosts. Just hold
> down <ctrl> while you click on the hosts you want to disable.

Oh, I was referring to enabling them after they've already been 
disabled.  The ones in the "Currently disabled tests" block.  They have 
"enable" buttons next to each host, but no obvious way to do more than 
one at a time.

Tom