[WIP] Add Linbox and deps

Currently this fails with:
```
Traceback (most recent call last):
  File "/home/ondrej/usr/bin/hit", line 13, in <module>
    sys.exit(help_on_exceptions(logger, main, sys.argv, os.environ, logger))
  File "/home/ondrej/repos/hashdist/hashdist/cli/main.py", line 169, in help_on_exceptions
    return func(*args, **kw)
  File "/home/ondrej/repos/hashdist/hashdist/cli/main.py", line 143, in main
    retcode = args.subcommand_handler(ctx, args)
  File "/home/ondrej/repos/hashdist/hashdist/cli/frontend_cli.py", line 42, in run
    self.profile_builder_action()
  File "/home/ondrej/repos/hashdist/hashdist/cli/frontend_cli.py", line 98, in profile_builder_action
    self.args.k, self.args.debug)
  File "/home/ondrej/repos/hashdist/hashdist/spec/builder.py", line 151, in build
    keep_build=keep_build, debug=debug)
  File "/home/ondrej/repos/hashdist/hashdist/core/build_store.py", line 377, in ensure_present
    artifact_dir = builder.build(config, keep_build)
  File "/home/ondrej/repos/hashdist/hashdist/core/build_store.py", line 551, in build
    self.build_to(artifact_dir, config, keep_build)
  File "/home/ondrej/repos/hashdist/hashdist/core/build_store.py", line 570, in build_to
    self.run_build_commands(build_dir, artifact_dir, env, config)
  File "/home/ondrej/repos/hashdist/hashdist/core/build_store.py", line 627, in run_build_commands
    self.build_store.prepare_build_dir(config, logger, self.build_spec, build_dir)
  File "/home/ondrej/repos/hashdist/hashdist/core/build_store.py", line 430, in prepare_build_dir
    unpack_sources(self.logger, source_cache, build_spec.doc.get('sources', []), target_dir)
  File "/home/ondrej/repos/hashdist/hashdist/core/build_store.py", line 656, in unpack_sources
    source_cache.unpack(key, target)
  File "/home/ondrej/repos/hashdist/hashdist/core/source_cache.py", line 376, in unpack
    handler.unpack(type, hash, target_path)
  File "/home/ondrej/repos/hashdist/hashdist/core/source_cache.py", line 801, in unpack
    create_archive_handler(type).unpack(infile, target_dir, hash)
  File "/home/ondrej/repos/hashdist/hashdist/core/source_cache.py", line 882, in unpack
    archive.extractall(target_dir, members)
  File "/usr/lib/python2.7/tarfile.py", line 2048, in extractall
    self.extract(tarinfo, path)
  File "/usr/lib/python2.7/tarfile.py", line 2085, in extract
    self._extract_member(tarinfo, os.path.join(path, tarinfo.name))
  File "/usr/lib/python2.7/tarfile.py", line 2169, in _extract_member
    self.makelink(tarinfo, targetpath)
  File "/usr/lib/python2.7/tarfile.py", line 2254, in makelink
    self._extract_member(self._find_link_target(tarinfo), targetpath)
  File "/usr/lib/python2.7/tarfile.py", line 2410, in _find_link_target
    raise KeyError("linkname %r not found" % linkname)
KeyError: "linkname 'fflas-ffpack-1.6.0/fflas-ffpack/utils/args-parser.h' not found"
```
I have no idea what this means.