`DS.Adapter.resolveMapConflict` can receive two arguments
Better YUIDocs
Merge pull request #890 from thomasboyt/docs

Better YUIDocs
Merge pull request #887 from tricknotes/remove-not-referenced-argument

`DS.Adapter.resolveMapConflict` can receive two arguments
Eliminate unused variables

I used jshint with '"unused": true' option.
Merge pull request #888 from tricknotes/eliminate-unused

Eliminate unused variables
bump ember to rc2
Ember source now comes from the ruby gem.
ember now comes the from ember-source gem

Reduce some confusion
Merge pull request #892 from stefanpenner/remove_extra_ember

ember now comes the from ember-source gem
link to s3 builds in README
Merge pull request #896 from fivetanley/readme-for-s3-builds

link to s3 builds in README
Merge pull request #891 from stefanpenner/upgrade_to_ember_rc2

Upgrade to ember rc2
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