(main) Remove a couple of lines of commented out dead code.
Fix issue with missing type check for multibind type.

The type check was never invoked because of misnamed method.
Fix yardoc for the central Binder classes

This makes a first pass at fixing yardoc for the central binder classes
(at least to the point that they do not crash yard). Expect more
complicated things to have more and better documentation.

Also includes fixes of some typos in code.