gates : Refactored to use lower case names
Removed MIGATES; fixes #225
gates: minor fix
combinational: refactoring to lowercase names
tests : combinationals and gates test refactoring and gate.py minor fix
Refactoring other modules
Merge pull request #247 from rvraghav93/gate_refactoring

Some more Refactoring - Added Missing NOT Gate test and removed MIGRATES