Add getSyncToken and setSyncToken to data store interface.

This allows local storage to hold onto the token across page refreshes.

lib/client.js

@@ -54,8 +54,6 @@ function MatrixClient(opts) {
             return _sendEventHttpRequest(self, eventToSend);
         });
     }
-    // track our position in the overall eventstream
-    this.fromToken = undefined;
     this.clientRunning = false;
 
     var httpOpts = {
@@ -986,7 +984,7 @@ MatrixClient.prototype.startClient = function(historyLen) {
         // client is already running.
         return;
     }
-    if (this.fromToken) {
+    if (this.store.getSyncToken()) {
         // resume from where we left off.
         _pollForEvents(this);
         return;
@@ -1038,7 +1036,7 @@ MatrixClient.prototype.startClient = function(historyLen) {
         }
 
         if (data) {
-            self.fromToken = data.end;
+            self.store.setSyncToken(data.end);
             var events = [];
             for (i = 0; i < data.presence.length; i++) {
                 events.push(new MatrixEvent(data.presence[i]));
@@ -1087,7 +1085,7 @@ function _pollForEvents(client) {
     }, 40000);
 
     client._http.authedRequest(undefined, "GET", "/events", {
-        from: client.fromToken,
+        from: client.store.getSyncToken(),
         timeout: 30000
     }).done(function(data) {
         if (discardResult) {
@@ -1152,7 +1150,7 @@ function _pollForEvents(client) {
             });
         }
         if (data) {
-            self.fromToken = data.end;
+            self.store.setSyncToken(data.end);
             utils.forEach(events, function(e) {
                 self.emit("event", e);
             });