api: no more sync'ed Viewport methods

- remove synchronized viewport methods: viewport MUST only be changed on main-thread
- when calling Map.setPosition() from another thread the position will be applied
  on the next main-loop iteration

vtm-web/src/org/oscim/gdx/emu/org/oscim/utils/ThreadUtils.java

@@ -0,0 +1,16 @@
+package org.oscim.utils;
+
+public class ThreadUtils {
+
+	public static void assertMainThread() {
+	}
+
+	public static boolean isMainThread() {
+		return true;
+	}
+
+	public static void init() {
+
+	}
+
+}