Properly report error stacks in Backbone.sync
Fix bug in method determining req'd objectStores

I was using "break" when I really meant "continue". Fixed things with
more conditionals.
Don't automatically set IDs when storing to IDB

Instead, force application to deal with IDs on its own.
Fix missing return value in Backbone.sync
Enable adding periods to periodizations
Don't reset Backbone.Relational.scope after every view

it causes problems. I don't think the "store" concept is very useful to
us but the rest of the package is nice so I don't know.
Properly serialized period.{start,stop}
Include information about periods' timespans in periodization list
Remove stray console.log