whew. finally done block.py.

the msdos table primary/extended/logical thing was a pain but the
logic wasn't too bad.

aif/disk/lvm.py

@@ -0,0 +1,13 @@
+class PV(object):
+    def __init__(self, partobj):
+        self.devpath = None
+        pass
+
+class LV(object):
+    def __init__(self, lv_xml, pv_objs):
+        pass
+
+class Group(object):
+    def __init__(self, vg_xml, lv_objs):
+        self.devpath = None
+        pass