New design for Conversation Activity.

1) Move to Fragments for the list view.
2) Switch to CursorLoader from my jankey self-managed cursor.
3) Add session security logic to the ActionBar.
4) Fix colors to be less ugly.

src/org/thoughtcrime/securesms/database/loaders/ConversationLoader.java

@@ -0,0 +1,23 @@
+package org.thoughtcrime.securesms.database.loaders;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.support.v4.content.CursorLoader;
+
+import org.thoughtcrime.securesms.database.DatabaseFactory;
+
+public class ConversationLoader extends CursorLoader {
+  private final Context context;
+  private final long threadId;
+
+  public ConversationLoader(Context context, long threadId) {
+    super(context);
+    this.context  = context.getApplicationContext();
+    this.threadId = threadId;
+  }
+
+  @Override
+  public Cursor loadInBackground() {
+    return DatabaseFactory.getMmsSmsDatabase(context).getConversation(threadId);
+  }
+}