added CBV vs CBN worksheet

src/Lesson1/CBV_vs_CBN.sc

@@ -0,0 +1,10 @@
+def firstCBV(x: Int, y: Int): Int = x
+
+def firstCBN(x: Int, y: => Int): Int = x
+
+def loop: Int = loop
+
+firstCBV(4, 5)
+firstCBN(4, 5)
+firstCBN(4, loop)
+//firstCBV(4, loop)