Rebuild SettingsStore to be better supported

This does away with the room- and account-style settings, and just replaces them with `supportedLevels`. The handlers have also been moved out to be in better support of the other options, like SdkConfig and per-room-per-device.

Signed-off-by: Travis Ralston <travpc@gmail.com>

src/settings/RoomSettingsHandler.js

@@ -0,0 +1,56 @@
+/*
+Copyright 2017 Travis Ralston
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+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 Promise from 'bluebird';
+import SettingsHandler from "./SettingsHandler";
+import MatrixClientPeg from '../MatrixClientPeg';
+
+/**
+ * Gets and sets settings at the "room" level.
+ */
+export default class RoomSettingsHandler extends SettingsHandler {
+    getValue(settingName, roomId) {
+        const room = MatrixClientPeg.get().getRoom(roomId);
+        if (!room) return Promise.reject();
+
+        const event = room.currentState.getStateEvents(this._getEventType(settingName), "");
+        if (!event || !event.getContent()) return Promise.reject();
+        return Promise.resolve(event.getContent());
+    }
+
+    setValue(settingName, roomId, newValue) {
+        return MatrixClientPeg.get().sendStateEvent(
+            roomId, this._getEventType(settingName), newValue, ""
+        );
+    }
+
+    canSetValue(settingName, roomId) {
+        const cli = MatrixClientPeg.get();
+        const room = cli.getRoom(roomId);
+        const eventType = this._getEventType(settingName);
+
+        if (!room) return false;
+        return room.currentState.maySendStateEvent(eventType, cli.getUserId());
+    }
+
+    isSupported() {
+        return !!MatrixClientPeg.get();
+    }
+
+    _getEventType(settingName) {
+        return "im.vector.setting." + settingName;
+    }
+}