Sample itinerary redirect

If user tries to access itinerary.html?id=sampleID, redirects to
sample-itinerary page so can't edit
Likewise, if accidentally gets to sample-itinerary.html?id=notSampleID,
redirects to itinerary.html for editing
Error checking on existing storage

Pages check whether anything has been stored yet; if so, parses existing
stored JSON, otherwise writes sample itineraries to storage
Merge pull request #48 from kaitlinhuben/kh-edit-itinerary

Integrating storage