Ability to pass arguments to functions by name

Ability to pass arguments like this:
```
func foo(val1:String = "c", val2:String = "c"):
    print(val1)
    print(val2)

foo(val2 = "a") # prints "c a"
foo(val2 = "a", val1 = "b") # prints "b a"
```
Here is the equivalent in python explained: https://treyhunner.com/2018/04/keyword-arguments-in-python/
