Eep19

Since different kinds for generators had already been introduced, this branch adds support for EEP19's `&&` operator, as `|`;  
such as in: (coloration set to Haskell)
```haskell
zip :: ([<term>], [<term>]) -> [{<term>,<term>}]
zip ([X|Xs], [Y|Ys]) =
    [{X',Y'} | X' <- [X|Xs]
             | Y' <- [Y|Ys]]
zip ([], []) = []
```  
More info there: 
http://www.erlang.org/eeps/eep-0019.html