Inherit reactions & fix PEP8

[AnonymousX86]

General

• Add inheritance of Reaction class.
• All files should be ended with a single empty line. Not only .py.

PEP8

• Imports should be split to three categories: built-ins, required, own.
• Imports should be sorted alphabetically.
• Python uses snake_case.
• Lines should be seventy-nine characters long or less.
• Between classes and functions there should be two empty lines (except inside statements like if or with). Everywhere else one or none.

[ArjunSharda]

Thanks for your changes! Merging this soon today!