Delete cached directory that was preventing branch switching.
Fix Calendar plugin path references.

Plugin used WP's plugins_url() function with the second argument of
basename(dirname(__FILE__)) which would end up returning something like
.../wp-content/js/lib.js when it actually wanted to return
../wp-content/google-calendar-events/js/lib.js.
Removing the reference to the parent directory actually fixes this.  I
don't know how.
Modify gitignore for better use of wildcards.