Add tox configuration to the repository

[he0s]

Add tox configuration file, that can be used to run different kind
of tests like syntax test, any custom tests and so forge.

This configuration has some check ignored, the list of them is the following:

N801 # Should be fixed (e.g.: class name 'Graph_UUID_Status' should use CapWords convention)
N802 # Should be fixed (e.g.: function name 'ByID' should be lowercase)
N803 # Should be fixed (e.g.: argument name 'ID' should be lowercase)
N805 # Should be fixed (e.g.: first argument of a method should be named 'self')
N806 # Should be fixed (e.g.: variable 'ID' in function should be lowercase)
N815 # Should be fixed (e.g.: variable '_lib_byID' in class scope should not be mixedCase)
N816 # Should be fixed (e.g.: variable 'streamJS' in global scope should not be mixedCase)

Some checks were skipped by adding # noqa keyword to the code.

All the changes have passed the flake8 tests as well as running unit tests from test.py script.