fixed documentation bug as per issue #4029
Merge pull request #2495 from perseus0807/4029_iterables

fixed documentation bug as per issue #4029
Add Vinit Ravishankar to AUTHORS/aboutus. Welcome to SymPy!
Merge pull request #2511 from smichr/auth

Add Vinit Ravishankar to AUTHORS/aboutus. Welcome to SymPy!