remove (circular) dependency on sync in session

src/session.js

@@ -1,34 +1,28 @@
-class Session {
-	// sessionData has device_id and access_token
-	constructor(sessionData) {
+export default class Session {
+	// sessionData has device_id, user_id, home_server (not access_token, that is for network)
+	constructor(sessionData, storage) {
 		this._sessionData = sessionData;
+		this._storage = storage;
+		this._rooms = {};
+		this._syncToken = null;
 	}
 
-	loadFromStorage() {
+	load() {
 		// what is the PK for a session [user_id, device_id], a uuid?
 	}
 
-	start() {
-		if (!this._syncToken) {
-			do initial sync
-		}
-		do incremental sync
-	}
-
-	stop() {
-		if (this._initialSync) {
-			this._initialSync.abort();
-		}
-		if (this._incrementalSync) {
-			this._incrementalSync.stop();
-		}
-	}
-
 	getRoom(roomId) {
 		return this._rooms[roomId];
 	}
 
-	applySync(newRooms, syncToken, accountData) {
+	createRoom(roomId) {
+		const room = new Room(roomId, this._storage);
+		this._rooms[roomId] = room;
+		return room;
+	}
 
+	applySync(syncToken, accountData, txn) {
+		this._syncToken = syncToken;
+		txn.session.setSyncToken(syncToken);
 	}
 }