First step of data flow refactoring.

This moves all data source connections into the TrackDataHub.

There are still many things to (re)do here:
- Optimizations about when the listeners are registered
- Optimizations about what data each TrackDataListener is interested in
- When activities are restarting, send new data since they were stopped (instead of doing a full reload)
- Proper double-buffering of Location objects (some listeners are interested in double-buffering all points, while others are only interested in double-buffering sampled points)
- etc.

MyTracks/res/layout/listitem.xml

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+Copyright 2010 Google Inc.
+
+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.
+-->
+<LinearLayout
+  xmlns:android="http://schemas.android.com/apk/res/android"
+  android:layout_width="fill_parent"
+  android:layout_height="wrap_content"
+  android:padding="2dip"
+  android:orientation="vertical">
+  <TextView android:id="@+id/maplistitem"
+    android:layout_width="fill_parent"
+    android:layout_height="wrap_content"
+    android:textSize="9pt"
+    android:textStyle="bold"
+    android:textColor="#fff"
+    android:singleLine="true"/>
+    <TextView android:id="@+id/maplistdesc"
+      android:layout_width="fill_parent"
+      android:layout_height="wrap_content"
+      android:textSize="8pt"
+      android:singleLine="true"/>
+    <TextView android:id="@+id/maplistpublic"
+      android:layout_width="fill_parent"
+      android:layout_height="wrap_content"
+      android:textSize="7pt"
+      android:singleLine="true"/>
+</LinearLayout>