WIP: libsyndicate refactoring--separate HTTP, system, and crypto
routines into their own files.  Make it possible to build libsyndicate
and UG without a build-in HTTP daemon.
WIP: UG refactoring: make network, storage, and consistency routines
part of the main code body, not the fs-specific code body.
WIP: Google Native Client (NaCl) build targets (libsyndicate-nacl, UG-nacl).
These do NOT work yet.
Still to come: NaCl storage and network routines for the UG, using
libnacl_io.