Switch from Jasmine to Mocha + Sinon + Chai-bdd-expect

See #73, https://github.com/nilbus/Backbone.dualStorage/pull/73#issuecomment-44101373

- Rename integration_spec to acceptance_spec.
- Convert acceptance specs to mocha.
- Use an alternate idAttribute in all examples.
- Going forward, all features will be tested using Models and Collections.
- Moved legacy unit tests to jasmine/ for later conversion.
Mark acceptance tests as "legacy"

...because I want to refit them into this structure:

- Basic persistance
  - fetch
    - option: add
    - option: merge
  - save
    - create
    - update
    - updated attributes in server response
      - fetch
      - create
      - update
  - destroy
- Model and Collection interaction
  - Fetch collection, then fetch update model
- Override modes
  - mode
    - local
    - remote
  - override via
    - attribute
    - method
    - options
- Offline caching
  - Collection.syncDirtyAndDestroyed
    - Collection.syncDirty
    - Collection.syncDestroyed
  - Collection.dirtyModels
  - Collection.destroyedModelIds
  - fetch is local when there are dirty/destroyed
  - Temporary id for created models until synced
- Offline detection
  - Backbone.DualStorage.offlineStatusCodes
    - array
    - function
- Callbacks
  - options.dirty set when offline
  - When offline
    - no local store: error
    - with local store: success
  - When online
    - error code: error
    - 200 code: success
  - Delivery
    - success/error callback
    - $.Deferred
- Pre-parsing
  - Modellection.parse
  - Modellection.parseBeforeLocalSave
- Modellection.storeName
Implement acceptance tests for basic persistence