REACH-141 Can't save more than one home workspace in web version of flood

[Link to the task](http://adsk-oss.myjetbrains.com/youtrack/issue/REACH-141).

To work correctly, this PR requires [renaming message types](https://github.com/pboyer/flood/pull/101)
It looks like this is a check to see if it is the home workspace.  That is, if the workspace is at index 0, it must be the home workspace.  This doesn't sound like a safe way to do this check.  Why not just do an explicit check?