Added IC 7485
Added 4-bit ALU IC 74181
Misc fixes to sig_gen.py
Change coveralls package
Merge pull request #254 from debugger22/coveralls-new

Change coveralls package
Merge pull request #253 from debugger22/miscfix

Misc fixes to sig_gen.py
Add .coveragerc
Merge pull request #251 from Vandan-V-Phadke/add_ic_74181

Add ic 74181
Merge pull request #255 from debugger22/coveralls-new

Add .coveragerc