[python-pytrakt] Cleanup: Remove old (python<3.0) super constructor syntax

[glensc]

class C(B):
    def method(self, arg):
        super().method(arg)    # This does the same thing as:
                               # super(C, self).method(arg)

• https://docs.python.org/3/library/functions.html#super
• https://stackoverflow.com/questions/576169/understanding-python-super-with-init-methods

[glensc]

Carried to my fork:

• glensc/python-pytrakt@75abb0e