tommcfarlin/WordPress-Plugin-Boilerplate — pull request #125 by jameswlane (2013-11-15 11:40:50+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 not cause an error, the extra slash can be removed.