Deletion of plugin folder should consider symlinked directories

Default behavior for wordpress when deleting a plugin is to recursively empty the folder by deletion before attempting to delete the parent folder.

I propose that before doing a recursive delete, the parent folder should be attempted for removal using rmdir() and unlink(). rmdir is capable of removing junction’d folders (NTFS file system) and unlink can remove symbolic links. After attempting to remove the directory through those two methods, if both fail (99% of the time they will fail) then continue to do a recursive file deletion before a traditional rmdir, as is already done.

The purpose of this is to allow the deletion of a plugin without destroying the source data when a plugin is installed via symlinking or directory junctioning. In some environments, its useful to install plugins via this method.