Ending support for Python 2

[Mithil467]

Python 2 support was added initially because it was really easy to do so. But it is not really necessary. The advantages are minimal, and the development overhead is far greater with testing code on both Python versions and ensuring that code is compatible with Python 2.

So moving on, all the code supporting Python 2 will be removed and further features will be developed by keeping Python 3 in mind.

Any contributions towards achieving this is really appreciated! 😄

[Mithil467]

Python 2 can still make use of the release v0.2.2 which can be installed with the command pip install mitype==0.2.3 although upcoming versions won't support it.