Notify that a default adapter type has been selected

This will notify that in the absence of custom adapter
a default has been selected.
Test registerEnumTransform on Adapter class instead of adapter instance

As the registerTransform is call on the class, the registerEnumTransform should operate on the class as well
Allow call to registerEnumTransform on Adapter class, fix #786
Fixed non camelCase variable
rollback support for hasMany relationships that are not part of the transaction
Merge pull request #898 from ghempton/hasmany-rollback

Fix rollback for hasMany relationships that aren't part of the transaction
Transition from client IDs to record references

In Ember Data, there needs to be a mechanism for the system to refer to
a record that has not yet been loaded. These references need to be as
cheap as possible so that loading and processing data does not require
materializing many full-blown DS.Models all at once.

Previously, the mechanism for referencing unloaded/unmaterialized records
was the client ID, a monotonically increasing number. Metadata about the
unmaterialized record was saved in several different data structures in
the store, indexed by client ID.

Unfortunately, as the needs of Ember Data have grown, the number of data
structures in the store have increased beyond their initial scope, leading
to confusing, opaque code.

This commit replaces almost all of the uses of client ID with the notion
of a record reference. A reference is a simple JavaScript object that
contains all of the metadata for a single record.

For example, when you load data into the store via `load`, it will
be saved inside the record reference. When you find the record, via
e.g. `App.Post.find(1)`, the materialized record will also be
saved inside the record reference.

This commit also comes with several convenience methods for dealing with
record references on the store.
Clean up DS.Store preamble
Move transaction helper to DS.Transaction
Extract record array responsibility

This extracts record array management responsibility out of DS.Store
and moves it into a new DS.RecordArrayManager.
remove transaction-level book-keeping
Merge pull request #895 from ghempton/simplify-transactions

Simplify Transaction Implementation
Merge pull request #787 from bobbus/fix-register-enum-transform-on-class

Allow calling registerEnumTransform on the Adapter class
use a transaction to save records
Merge pull request #690 from trek/notify-that-a-default-adapter-is-used

Notify that a default adapter type has been selected
Merge pull request #902 from tchak/schedule-save

use a transaction to save records
basic adapter should move records out of uncommitted state
Merge pull request #894 from tchak/basic-loader

basic adapter should move records out of uncommitted state
Update basic-adapter
Update didSave API