- Have TagOrderStore listen for MatrixSync actions so that it can initialise
tag ordering state.
- Expose an empty list until the client has done its first sync and has
fetched list of joined groups
This introduces a generic way to register certain events emitted by
the js-sdk as those that should be propagated through as dispatched
actions.
This allows the store to treat the js-sdk as the "Server" in the
Flux data flow model. It also allows for stores to not be aware
specifically of the matrix client if they are only reading from it.
