progs/demos: fix glut initialization calls

Remove glutInitWindowPosition() calls to play nicer with window managers.

Move glutInitWindowSize() calls before glutInit() so the the default window
size can be overridden by the -geometry cmd line option.
diff --git a/progs/demos/spectex.c b/progs/demos/spectex.c
index 6ab1191..c1dada9 100644
--- a/progs/demos/spectex.c
+++ b/progs/demos/spectex.c
@@ -239,13 +239,9 @@
 
 int main( int argc, char *argv[] )
 {
-
-   glutInit( &argc, argv );
-   glutInitWindowPosition( 0, 0 );
    glutInitWindowSize( 300, 300 );
-
+   glutInit( &argc, argv );
    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
-
    glutCreateWindow( "spectex" );
 
    Init();