This commit fixes issue #276. If $GOPATH includes multiple paths (as
allowed by the spec), Cobra cannot guess the project path, so now init
bails out if a relative path is given. The original behaviour is not
changed, if $GOPATH only contains a single path (as in most cases).
* 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
