more fixes in the build, related to CMake and some error (don't delete a void* pointer!)

revert BasicDemo.cpp to original Bullet 2.82 state

btgui/CMakeLists.txt

@@ -1 +1,3 @@
+if (OPENGL_FOUND)
 SUBDIRS(  Gwen OpenGLWindow )
+endif(OPENGL_FOUND)

btgui/OpenGLTrueTypeFont/opengl_fontstashcallbacks.cpp

@@ -180,7 +180,7 @@ void InternalOpenGL2RenderCallbacks::updateTexture(sth_texture* texture, sth_gly
 
 				glDeleteTextures(1, id);
 				//delete id;
-				delete texture->m_userData;
+				delete id;//texture->m_userData;
 				texture->m_userData = 0;
 			}
 

btgui/OpenGLWindow/premake4.lua

@@ -43,4 +43,3 @@
 					"../OpenGLWindow/MacOpenGLWindow.mm",
 			} 
 		end
-