Add lab session 6

Handed in on Jan 24.

Change-Id: Ie36f75a2819ae0564f2a4f99bbb859a452156c22
diff --git a/p6/data/puntcritic.dat b/p6/data/puntcritic.dat
new file mode 100644
index 0000000..3f61521
--- /dev/null
+++ b/p6/data/puntcritic.dat
@@ -0,0 +1,2 @@
+#P   T    dP  dT  V
+46.6 37.5 1.5 1.1 50.0