whew. finally done block.py.

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

aif/disk/mdadm.py

@@ -0,0 +1,11 @@
+class Member(object):
+    def __init__(self, member_xml, partobj):
+        self.xml = member_xml
+        self.device = partobj
+        self.devpath = self.device.devpath
+        pass
+
+class Array(object):
+    def __init__(self, array_xml):
+        self.devpath = None
+        pass