Join takes a SoCo instance, use more topology
Quicker network call to determine visibility
merging with master
Merge pull request #136 from lawrenceakka/topology-fixes

Join takes a SoCo instance, use more topology
Added isinstance(metadata, str) check before running encode on metadata.
Closes #134
Merge pull request #135 from petteraas/str_check_before_encode

Added isinstance(metadata, str) check before running encode on metadata. Closes #134