Pointer arithmetic + array indexing syntactic sugar on pointers

[MovingtoMars]

Another TODO.

My idea: Add uintptr. You can convert any pointer type to uintptr and uintptr to any pointer type.

[kiljacken]

While a neat way to handle arbitrary pointer manipulation, we should probably allow size-aware pointer offsetting, most likely by using array index syntax, e.g.:

thing: *Thing;
thing[n] == uintptr(thing) + n*sizeof(Thing)

[felixangell]

@kiljacken :+1: