De-dupe random menu filenames by truncating at first dot, rather than last.
Fix for one of the problems described in issue #380. bbs.menu("random*"); would display column-width-specific files (e.g. random.132col.msg) even when they weren't appropriate for the current user terminal width. This is fixed by truncating the filenames matching the requested pattern at their first-dot rather than the last. The downside is, you can't have a set of random.#.* files, where # is the unique part of the filename and * is the file-type extension. Just use the naming pattern "random-#.*" instead (or something similar) instead.