Lots of progress on Elm benchmarking!

[justinlubin]

Bugs fixed

• Unification adapter now properly sets last argument for catamorphisms
• Polymorphic variants now have their arguments type checked
• Fix recursion scheme extraction bug where branch parameters aren't correctly checked for replacement
• Fix bug where bin/main did not replace recursive function references with the new (free variables) parameter version
• Fix bug where list patterns were parsed incorrectly
• Free variable extraction in bin/main now correctly subtracts out variables defined in the stdlib
• Fix if-lifting/deforestation/cata normalization related bugs

Synthesis features

• Add support for Result, List, and Basic functions, and many of these as components to the standard library
• Make recursion scheme extraction more forgiving, returning an exp instead of an exp option
• Add the notion of "builtins" to the component library so we can use e.g. ++ in our component definitions
• Add "inlining" rules for || and && (treat them as syntactic sugar)
• Recursion scheme extraction now works when the structurally descending argument is something other than the last argument
• Add second match fusion rule

Frontend features

• Add make-report subcommand
• Subcommands now regenerate standard library when needed