progs/trivial:  Label program windows with actual program name

Each of these programs previously called itself "First Tri" which was a
little confusing.  Could have left one as "First Tri", but the trouble
then is that people would still clone that file & we'd end up with
another thousand first tri apps...
diff --git a/progs/trivial/poly.c b/progs/trivial/poly.c
index 2f254de..8944f14 100644
--- a/progs/trivial/poly.c
+++ b/progs/trivial/poly.c
@@ -124,7 +124,7 @@
     type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
     glutInitDisplayMode(type);
 
-    if (glutCreateWindow("First Tri") == GL_FALSE) {
+    if (glutCreateWindow(*argv) == GL_FALSE) {
 	exit(1);
     }