documentation

[quasarbright]

• copy peg to typed-peg
• assert type error in stlc on typed racket
• get-racket-referenced-identifiers in binding operations
• convert rest of typed peg to typed racket, sexpr broken
• multipass stub
• some specification documentation
• provide get-racket-referenced-identifiers
• stlc hash lang
• racket-references runs with binding-operations version
• some specification documentation updates
• simpler stlc lang using host interface that provides all
• test symbol collections
• baby peg
• typed peg builds, commented out tests
• complete specifying languages documentation
• complete compiling documentation