This patch updates our boost package to version 1.60.0.  It also fixes 
several dependent packages to build with this later version.  I've been 
able to verify the x86-64 builds for all packages in `guix refresh -l 
boost`, except for several packages that already fail to build in 
current master (e.g. opam, simple-scan, strigi, hydra, shogun).

-- 
`~Eric