Ignore all tmp and log files but preserve the directory structure

This takes the change from #339 and makes it case insensitive so that CakePHP projects from both before and after the rename ignore the appropriate files.

the current version of Cakephp (2.x) renamed the config folder to Config. adding core to the list of files to ignore as this contains security salts.

Don't ignore empty files meant to preserve the file structure of an application within a git repository for later deployment