[twill] problems with form filling works in 0.8.3 but not in 0.8.4a10

[Titus Brown]

-> I'm looking at this problem too, and what I've come up with is that
-> 
-> commands.formvalue(formnum, fieldname, value) is insufficent for the 
-> task of selecting, and deselecting, checkboxes.
-> 
-> The issue lays in that the action needs the following data:
-> What Form?
-> What Checkbox Name?
-> What Checkbox Value?
-> On or Off?
-> 
-> The API as it stands will select or deselect a single, or, if we let
-> 
-> commands.formvalue(formnum, fieldname, 'foo')
-> 
-> work, will allow selection, but not de-selection, of checkboxes.
-> 
-> Going back to the hackish API that PBP used to use, we could allow:
-> 
-> commands.formvalue(formnum, fieldname, '+foo')
-> commands.formvalue(formnum, fieldname, '-foo')
-> 
-> as well.
-> 
-> Please see attached patch and tests.

Hi, stephen,

Thanks for this fix; I've applied it.  The root of the problem is that
I'd forgotten that checkboxes could do this ;).

cheers,
--titus