add ImplicitCloth demo, by Stan Melax

add SimpleOpenGL3App, used in ImplicitCloth demo. The Bullet 3.x demos should use this as a template, it will clean up some of the mess.

btgui/OpenGLWindow/LoadShader.cpp

@@ -3,7 +3,7 @@
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include "Bullet3Common/b3Logging.h"
+
 
 // Load the shader from the source text
 void gltLoadShaderSrc(const char *szShaderSrc, GLuint shader)
@@ -90,8 +90,8 @@ GLuint gltLoadShaderPair(const char *szVertexProg, const char *szFragmentProg)
 								 &actualLen,
 								 infoLog);
 
-		b3Error("Warning/Error in GLSL shader:\n");
-		b3Error("%s\n",infoLog);
+		printf("Warning/Error in GLSL shader:\n");
+		printf("%s\n",infoLog);
 		glDeleteProgram(hReturn);
 		return (GLuint)NULL;
 	}