Most functions and classes lack documentation

[andreped]

We should add descriptions on what the different functions and classes do.

This should be done in a standardized manner. Probably something like this, that PyCharm suggests:

def test_function(p1, p2, p3):
    """
    test_function does blah blah blah.

    :param p1: describe about parameter p1
    :param p2: describe about parameter p2
    :param p3: describe about parameter p3
    :return: describe what it returns
    """ 
    pass

[andreped]

Fixed in 3d90fe5be93c34a5dcca947b9a508681efc3d904

Now almost all functions have descriptions. Will further improve this in the future, but at it should be easier for new developers to contribute.