* Refactoring code that unnecessarily declares a map before making it.
* Cleaning up gpl3 formatting to match other licenses.
* Adding functionality that allows specifying custom license header
and text in cobra config.
* Using license header and text as templates so that they can use
template variables (for custom and gpl3 licenses).
* Adding ability to specify no license.
* Adding custom license example to README.
* Moving final return outside of if-else
* Removing type declarations that Go can infer from values
* Cleaning up some existing comments
* Changing snake_case variables to camelCase
