Issue #2245239 - Provide a mechanism for third-party modules to specify location of custom Checks and Reports; allow checks to be added to existing reports. Also fixed a notice in the Drupal Status report.
Issue #2245239 - Fixed bug with report name refactoring, don't attempt to require a check file if the class already exists.
Issue #2245239 - Documenting how to add custom Reports and Checks; rewrote README.