Remove the broken IO::Filtered class
Rewrite BufferedFile as a standalone class The generic Filtered template is unable to account for the complexities of buffering a seekable object. In particular, relative seeks were broken. I may revisit the template form at a later date if I come up with a workable design. For now its use is discouraged.
Add activation check to the rest of Filtered's virtual functions This fixes a bug manifesting in builder where a put call that triggers a BufferedFile's buffer flush causes the buffer contents to be written to the file twice.
Move files to prepare for assimilation into core