Python 3 ism
get_workspace_by_path() now takes a filter function
Start of refactored and cleaned-up create_workspace/share_dir.
Re-work create workspace to use new api.py
Do a better job of matching paths. Bump protocol version and plugin version. Normalize persistent.json on startup.
Respond to pings with pongs.
Fix permissions when sharing publicly. Give feedback when leaving a workspace.