New APIs, fewer bugs, more performance

• remove an unnecessary copy in the read path
• add documentation for Server_unix_9p
• add a shell subcommand for the CLI with history and line-editing
• server: allow per-connection state
• unix: transform Unix.EPIPE into `Eof
• when pretty-printing, don't print payloads
• add wstat/update to client API
• lofs: sequential read/write increased by 9-10x
• server: handle errors in the dispatcher loop
• client: allow clients to handle I/O errors and recover

Additional APIs, new build system

• Remove OASIS from build system
• Remove use of -pack, now use the index module Protocol_9p with aliases
• Expose previously hidden Response.sizeof_header
• Expose previously hidden Response.Read.sizeof_header
• Add Request.sizeof_header
• Add Request.Write.sizeof_header

Attach message handling changes

• add version/attach mount debug messages
• pass initial connection attach to receive callback handler

Minor bugfixes

• respect the negotiated message size in read
• add a LICENSE file

Initial release

• support for 9P2000.u (Linux-compatible)
• CLI which can act as both client and server