ascii notation for most iris operators.

- all ascii notation is marked "only parsing" so this PR shouldn't
  change anything for anyone using only unicode notation.
- the algorithm for creating an ascii notation is pretty simple.
  - \ast -> *
  - \triangleright -> |>
  - \vee -> \/
  - \wedge -> /\
  - \forall -> forall
  - \exists -> exists
  - \ast -> **