Previously a Lambda function taking natural number arguments `A1` to
`An` would be compiled to a circuit with arguments `x1` to `x(n+1)`
where argument `xi` in the circuit for i<(n+1) stands for argument
`A(n-i)` and `x(n+1)` stands as an unused variable.

Current channge omits the final variable and renames the rest, so
that the compiled circuit will have appropriate argument order and
type corresponding to the relevant STLC term.

Note that this changes how to input coproduct type circuit variables.

A

Adds a `library` flag which can be included while using Geb as a
binary to print the standard library alongside the compiled STLC or
Geb term.

Adds documentation for the new standard library flag.

Introduces `--test` flag using `-t` for binary usage. When used with
`-p`, given a compiled VampIR function of form `def foo x1 ... xn =
{body};` produces a test equality `foo x1 ... xn = y;` printed after
the entry function.

…test-flag