just include gtkmm.h and be done with it

[Martin Metzker <martinmetzker gmx net>]

Hello World!

I just finished up the last work of the first version of my software.
While doing that I remembered something I read in the Gtkmm tutorial.
Iirc it said
#include <gtkmm.h>
is bad practice because the overhead is rather big, which is not
desireable. I tried it. I went through all my header files and included
only the neccessary headers e.g. <gtkmm/window.h>. The resulting program
is 412K big. The original version which simply includes gtkmm.h is 420K.
So is it really worth it including single header files?

greets

Martin