tommcfarlin/WordPress-Widget-Boilerplate — pull request #23 by jameswlane (2013-11-14 21:42:24+00:00)
Title: Removed the trailing slash

According to http://codex.wordpress.org/Function_Reference/plugin_dir_path, plugin_dir_path gets the filesystem directory path with trailing slash. Even tho two slashes will cause a error, the extra slash can be removed.