Updating cl-cffi-gtk to cffi version 0.11.2

Warning: cl-cffi-gtk no longer works with older versions of cffi.

This is a posting from Liam Healy from http://lhealy.livejournal.com/,
which explains the change of cffi version 0.11.2 due to bare references of
structures.

Apr. 28th, 2012
06:31 pm - mem-aref and mem-aptr in CFFI

"The master branch of CFFI has the cffi-libffi system, which permits passing
and returning structures by value. As part of that addition, some of the
syntax for structures has changed, even without loading that system.
Before, "bare structure" references were permitted, and they were
interpreted to mean pointers. Now, the syntax to specify a structure type is
(:struct name) for the structure by value, and :pointer or
(:pointer (:struct name)) for the structure by reference. The bare structure
form is still accepted, with a style warning.

The function mem-aref returns an element of the array, an object; since we
now can translate foreign structures, that includes structures. If the type is
designated as (:struct name), that means a CL representation of the
structure will be returned. By default (with no translate-from-foreign
method defined), that is a plist. If you want a pointer instead, use the new
function mem-aptr. As a special case, using the bare structure type
specification, mem-aref still returns a pointer, but if you use the new form,
you need to call mem-aptr to get the pointer instead of the object
translated into CL."