Move dispatcher into a subdirectory

We're expecting to have a whole bunch of types for the dispatched payloads, so pull the thing into a directory we can throw them in.

src/stores/SessionStore.js

@@ -14,7 +14,7 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
-import dis from '../dispatcher';
+import dis from '../dispatcher/dispatcher';
 import {Store} from 'flux/utils';
 
 const INITIAL_STATE = {