Add a few bugs, add (declare), chibi binary parameters, a tiny chicken bugfix and log auto scrolling.

Add a (declare (debug)) form to all geiser-%s--with-buffer macros. Add a variable to autoscroll the messages buffer. Add a global parameter to add additional parameters to chibi binary.

The problem with chicken that this request fixes has the following root: The way geiser processes responses always expects the string "(format "(display '((result . t) (output . f)))" in the output. However, this does not happen with the latest chicken, as the (suppression prefix) doesn't actually suppress stuff, at actually creates a warning, which in turn gets interpreted by geiser as a corrupt retort. To go around this, I am printing this bogus "(format "(display '((result . t) (output . f)))" at the beginning of the initialization string. It is a dirty trick, but a "suppression prefix" is an even dirtier trick, so I didn't have many regrets about writing it.