* added VUFIND_CACHE_DIR environment variable to httpd-vufind.conf
* VUFIND_CACHE_DIR now being used for custom cache directory
* CacheManager will throw an exception if cache_dir is set in config.ini

Prevent adding a module if it's already in the list.
Because on some systems it's not possible to define environment variables, you should be able to add the module to the normal module list (defined at the top of this file). Problem occures when you work with different systems for dev/test/prod etc. and want to share the same code base.

Adapted language reporting tools from VUFIND-149 as part of module.

Renamed VuFind\CLI module to VuFindConsole for cleaner layout.  Changed return value for expire_searches.php so that "no searches were found to delete" is a success rather than a failure.