Fix blank screen issue [#18] (#26)

Author: ywnico

app/src/main/java/com/bytehamster/flowitgame/GLRenderer.java

@@ -83,6 +83,7 @@ public void onSurfaceChanged(GL10 gl, int width, int height) {
 
         gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
         gl.glMatrixMode(GL10.GL_PROJECTION);
+        gl.glLoadIdentity();
         GLU.gluOrtho2D(gl, 0, width, 0, height);
         gl.glMatrixMode(GL10.GL_MODELVIEW);
         debugOutput(gl);