Make all operators redefinable

[evhub]

Operators should be defined using a special binding system. An operator function should be bound to an operator, which should be given a level and (optionally) made reserved. Possible syntax:

bind :: +(x,y) = add(x,y)
infix :: mod(x,y) = x%y
bind :: + :: -(x,y) = sub(x,y)

[evhub]

For adding comparison operators:

bind :: = :: ≠(x,y) = x != y

For creating operators over multiple arguments:

bind :: +(x,y,z) = add(x,y,z)
bind :: *(__) = mul(__)

For creating a unary function:

bind :: ?(x) = bool(x)

For creating an open/close group:

bind :: "(x)" = str(x)

For redefining an operator:

bind :: + :: +(__) = add(__)

[evhub]

The default operators should be the same, but use special funcfloats wrapping Python instead of pure Rabbit.

Additionally, only these operators should be hardcoded and unredefinable:

#
;;
::
=   # You can redefine =, but that redefines the comparison =
:
.
\
§