bindings in type environment should use same type relation

[Stephen Chang]

Would it be less confusing to not have different syntax for environment bindings and other parts of a type rule.

So it would be better to write:

[x ≫ x- ⇒ τ1] ⊢ e ≫ e- ⇒ τ2

or

[x ≫ x- ⇒ : τ1] ⊢ e ≫ e- ⇒ : τ2

instead of something like

[x ≫ x- : τ1] ⊢ e ≫ e- ⇒ τ2

[Stephen Chang]

allow types at runtime; fixes #26, fixes #27

→ <<cset a90dcb7279d3>>

[Stephen Chang]

allow types at runtime; fixes #26, fixes #27

→ <<cset cefcf5e53b09>>

[Stephen Chang]

allow types at runtime; fixes #26, fixes #27

→ <<cset e1d9d0071427>>