use linear filter for stipple texture

src/org/oscim/utils/GlUtils.java

@@ -113,8 +113,8 @@ public class GlUtils {
 		}
 
 		return loadTexture(pixel, sum, 1, GLES20.GL_ALPHA,
-				//GLES20.GL_LINEAR, GLES20.GL_LINEAR,
-				GLES20.GL_NEAREST, GLES20.GL_NEAREST,
+				GLES20.GL_LINEAR, GLES20.GL_LINEAR,
+				//GLES20.GL_NEAREST, GLES20.GL_NEAREST,
 				GLES20.GL_REPEAT, GLES20.GL_REPEAT);
 	}