[twill] 0.7.3, one site fails in Python, noreadonly patch

[Titus Brown]

-> 3.  proposed patch to ignore readonly fields with rationale,

Hi, James,

I've finally added this into the -latest distribution.

I've added a 'config' command that lets you override read-only control
settings:

	config readonly_controls_writeable 1

If this is set to True, then 'fv' will make read-only controls
writeable when called.

cheers,
--titus