add procedure for testing if a symbol is bound or not
initial rework of swank:operator-arglist
more work on swank:operator-arglist

Still need to figure out how to handle built in procedures and
macros. User procedures work, but it currently chokes on #!optional
parameters and probably #!key too.
fix #!optional and #!key forms of swank:operator-arglist by returning
string

Still need to explore user defined macros and built in
procedures/macros.