- making oscimap default backend

- added about-screen
- added TreeTile for Tile lookup, dropping that HashMap
- using simple line-shader instead of std-derivatives one,
  about twice as faster here
- use distance calculation from MapRenderer - removing TileScheduler
- no need for MapGeneratorJob, pass MapTile directly to MapWorkers
- added two-finger tap gestures for zoom-in/out
- added tub/tron rendertheme
- started caching for oscimap
- add x/y coordinates to MapPosition, using it in MapRenderer
- create tag hash when needed
- no need for long tile coordinates max zoomlevel 31 should suffice

res/menu/options_menu_pre_honeycomb.xml

@@ -48,6 +48,9 @@
        <!--   <item
                 android:id="@+id/menu_info_map_file"
                 android:title="@string/menu_info_map_file"/> -->
+          <item
+            android:id="@+id/menu_info_about"
+            android:title="@string/menu_info_about"/>
     </menu>
 
     </item>
@@ -61,6 +64,9 @@
                 <item
                     android:id="@+id/menu_render_theme_osmarender"
                     android:title="@string/menu_render_theme_osmarender"/>
+                 <item
+                    android:id="@+id/menu_render_theme_tronrender"
+                    android:title="@string/menu_render_theme_tronrender"/>
                 <item
                     android:id="@+id/menu_render_theme_select_file"
                     android:title="@string/menu_render_theme_select_file"/>