Made a basic class for the user interface bar utilizing scene2d.  Does
not show up yet, but program does not explode into misery and pain.

Also added image files from TankWars project.
Setup a GameScreen and have been able to make the leftButton show up.
It's ugly as Hell, but it is a start.
Have four directional buttons in the lower right corner of the screen.
They light up when touched.  Wheeeeeee!
Deleted unnecessary ui package.
Added the uistage.act(delta) call in GameScreen render() and added
a World instance from com.badlogic.gdx.physics.box2d.World to
GameScreen.
Removed obsolete code from tank.
Added the Direction enum (as a public enum in SunderedSteel package) and
the SteelButtonListener.  Can make the tank move left and right across the
screen.
Updated background.
Moved code for rendering objects to respective objects.
Terrain is ready to be integraeted. Commented out stages so that it can
be seen when android app is run.
Sky background and terrain appear correctly on both Android and Desktop
versions. Tank does not appear at correct spot.
Tank is somewhat rotating correctly with terrain.  However, it appears
that the sprite is out of sync with the box2d elements.  Also the code
is becoming way too messy.
Added code to flip the tank in the direction it's moving.
Cleaned up code.
Added code to make sure that tank does not go off the screen and
crash the program with a segfault.
Made very minor performance improvement to moving the current tank.
Made tank width and tank height static class variables.
Pushed movement handling code to Tank class
Created flat terrain generator.  Can get turret to appear correctly with
tank under very controlled cirumstances, does not move with tank yet and
only shows up correctly when the terrain is flat.
Incorporated turret into box2d physics engine.