Implement Trenary C-style Operator

[flofriday]

Example

age = 43
print(age == 50 ? "Half a century baby!" : "Hey there.")

Note

I am not sure we should implement this. @Jozott00 what are your thoughts?

We used this one in the spec to describe the ?? operator but the ternary operator is not the easiest to read. However, it is useful to write quick conditions.

[flofriday]

I still have a problem with the parser rejecting the questionmark but I should be able figure that one out .

[flofriday]

Implemented