README: Update my email address
README: Update the ‘Status’ section

This patch removes the mention that v1.13 may be the last version I
release as a maintainer, since I may end up releasing a v1.14 at some
point.  But I am still looking for a new maintainer to take over.
Add unit test for undoing of whitespace effects.

Checks if whitespace effects are undone when changing coding style from
Drupal.

GitHub-Issue: 53
Merge remote-tracking branch 'upstream/master' into issue-53

Make the fork up-to-date.
Update constant `php-mode-modified`.