Revert "Constants should be set by init action"

This reverts commit 3e63e399d713bf08c9154280d65208e462607e1d.
Fix for "Notice: Undefined index: action in /wp-content/plugins/church-admin/index.php on line 413"
Merge branch 'hotfix/fix-undefined-index-action'
Merge pull request #2 from JonB/master

More fixes for PHP warnings.