Use typing module

[herczy]

In Python3.5+, the way of hinting at types is done by using the typing module (see https://docs.python.org/3.5/library/typing.html). This module is also available through pip on older Python versions (I checked it with 3.4 and 2.7), so there we'd only need an extra dependency.

Using this to extend the type checker we could implement i.e. type templates/generics:

```
T = typing.TypeVar('T')

def append(l: typing.List[T], i: T):
    l.append(i)
```

It would also remove the need to constantly use collections for specifying collection-like type hints and also make us more PEP484 compliant. (see issue #15)