DS.FixtureAdapter.findQuery takes type

Pass type into findQuery. This allows you to do custom query logic based
on what kind of fixtures are requested. Now you can switch your query
logic if Todo or Message is queried. This logic would normally be done
on the server, but you can implement it here for development purposes.
WIP on embedded records
Add doc for store.recordIsLoaded

References issue #500
cleanup load() & loadMany() for DS.Store
added callChangeEvents
relationships now indexed based on parent, child, parentKey, childKey
made keys for relationship changes be childKey+parentKey
changed relationship to be simple two sided, only 9 failing tests
removal from old manyArray when added to a new one works
added relationship pairs function and made coalescing work
deleting old code
deleting more old code
Make Em.RestAdapter begin a run loop before invoking callbacks after ajax successes.
Clear relationships before dematerializing

The relationship change object needs to look up the record type in the
store (so it can find and unset inverse associations). Dematerialization
needs to occur after that happens, as it removes it from the store's type
lookup table.
Start writing tests for the new API
Merge pull request #511 from lukemelia/auto-run-loop

Make Em.RestAdapter begin a run loop before invoking callbacks after ajax
Merge pull request #503 from dgeb/cleanup-store-load

Cleanup load() & loadMany() for DS.Store
Merge pull request #502 from ssured/patch-1

Add doc for store.recordIsLoaded
Merge pull request #492 from twinturbo/query-fixtures-with-type

DS.FixtureAdapter.findQuery takes type
refactor oneToManyChange into RelationhipChangeAdd and RelationshipChangeRmeove