Add -t option to allow easy test selection.

Action verbose option correctly.
Tweak operation counts. Add empty and new instances tests.
Enable comparisons across different warp factors. Change version.

Tools/pybench/Empty.py

@@ -0,0 +1,23 @@
+from pybench import Test
+
+class EmptyTest(Test):
+    """This is just here as a potential measure of repeatability."""
+
+    version = 0.3
+    operations = 1
+    rounds = 60000
+
+    def test(self):
+
+        l = []
+        for i in xrange(self.rounds):
+            pass
+
+
+    def calibrate(self):
+
+        l = []
+
+        for i in xrange(self.rounds):
+            pass
+