Beef up automation/tasks

* Add Gruntfile.js, package.json, .jshintrc, .editorconfig, and node_modules
* Rename phpunit.xml to phpunit.xml.dist to play nice with others
Improve localization

* Don't attempt to translate variables
* Add missing text domain
* PHPDoc to reflect changes
Update string-replace Grunt task

* Add 'dev' string-replace to bump all files except the readme Stable tag
* Change 'version' to 'build' to update all strings at built time
* Add 'string-replace:build' to build task
Improve parsing and retrieval of role slugs array

* Introduce ba_eas_get_default_role_slugs() to better create the role slugs array
* Use ba_eas_get_default_role_slugs() througout
* Condense some display logic and don't attempt translate variables
* PHPDoc cleanup
Move the load_textdomain method to early init

This is to make sure that plugins have ample time to load translations
Fixes for ba_eas_author_link()

* Don't bail early if there's no valid user ID
* Set a default value for $role to avoid PHP notices

Discovered while investigating issues with Co-Authors Plus
Temp/semi work-around for Co-Authors Plus issue

Due to the way Co-Authors Plus filters 'author_link', a later filter priority is needed to still get our filters to work... at least partially. As long as the author link being generated is that of a legitimate WP user, one listed in the users table, we will still be able to successfully filter. However, guest authors will not have their links filtered until a fix upstream is applied.

See Co-Authors-Plus PR #204 [https://github.com/Automattic/Co-Authors-Plus/pull/204] for the proposed fix.
WP Coding Standards cleanup
Remove screenshots

These have been moved to the assets folder
Fix indentation in edit-author-slug.php
Rearrange tasks in Gruntfile build task

Run string-replace before makepot, so the new pot file will have the correct version.
Bump to 1.0.2