[ccan] CCAN update for 2015-11

[Rusty Russell]

Hi!

        A quiet month, but I found myself needing an fd-returning fopen
call, so wrote pipecmd.  Much more activity over graph traversal from
David Gibson.

Module of the Month: cast (LGPL2.1+)
====================================

This is a simple module which provides macros to make casting safer and
more explicit.  In particular, "cast_const(char *, foo)" gives a warning
if foo isn't a "const char *".  Similarly, cast_signed() will only change
signedness, and cast_static() will only do casts which would have been
implicit in C.

New modules:
============
	pipecmd: fork a command with explicit fds attached.

Updates & bugfixes:
========================
	aga: many minor fixes, documentation updates (David Gibson)
        aga, agar: Dijkstra's algorithm (David Gibson)
        net: use close_noerr()
        noerr: add free_noerr()
        strgrp: add cosine similarity filter (Andrew Jeffery)

Cheers,
Rusty.