Extend 'demoFill()' with realistic example journeys

[nfreear]

Hi @timcoughlan,

It struck me that it would be useful to have some example journeys in JSON format, and that URL parameters, for example, ?demo=1 or ?example=2, could be used to load them.

• ?load=example-1 (?demo=1 could be an alias for this)
• ?load=example-2
• ?load=template (A 'blank' template, or demoFill() ?)

Relates to: issues #5, #6 & #9, pull request #11.

Yours,

Nick