Adding asm & hack samples

Those are the examples and the asm & hack (assembled) from the project 6 of
nand2tetris

asm-samples/Add.asm

@@ -0,0 +1,12 @@
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+
+// Computes R0 = 2 + 3  (R0 refers to RAM[0])
+
+@2
+D=A
+@3
+D=D+A
+@0
+M=D