Removes the CLA from the Contributors/Code guide

Replaces with the Community Guidelines
References: #880
Merge pull request #1640 from jtyost2/patch-2

Removes the CLA from the Contributors/Code guide
Fixed Captialization of Google Group and added Stack Overflow to support section
Merge pull request #1642 from jtyost2/patch-2

Fixed Capitalization of Google Group
Remove unnecessary comma
Merge pull request #1646 from jtyost2/patch-2

Remove unnecessary comma