Finishing webGI input interface

[heidihoward]

Currently, we need front end support for:

• setting client workload
• Raft basic parameters
• unidirectional links
• links with differing latencies
• downloading config as JSON
• basic input validation (client side)
• selecting examples (more detail in User selectable examples #60)
• batch requests and lazy update (Raft options) in advance settings

We need backend support for:

• basic input validation (server side)
• server failure (plus state machine failure if non persistent)
• client failure
• hub failure