small bug in ofxShader

There’s a minor bug in ofxShader which fails to inform you if your shader didn’t compile:

      glGetObjectParameterivARB( fragmentShader, GL_COMPILE_STATUS, &compileStatus );  
      if(compileStatus > 0) {  
         printf("fragmentShader compiled \n");  
      } else if (compileStatus == 1) {  
         printf("!! fragmentShader compilation issues, status : %i !!\n", compileStatus );  

compileStatus is either 0 or 1, so the second printf never gets called.

It would also be great if an error message was printed when the shader file was not found (due to wrong path etc).