Compare Running configuration to written when captured on LM

Just now, mnagel said:

Not only that, but comparing in some cases is very painful.  When we used to use Nagios, we had checks that worked very well for the ASA since they use a cryptochecksum (this was trivial since we just scanned all the files in one pass, compared and submitted passive check results for any problems -- LM needs something similar, probably via the API).  For IOS there are a bunch of elements instantiated at startup that are not in the saved config, so while you could perhaps fashion a suitable filter, it would be brittle. Other platforms might be OK, just depends.

FWIW, we do use a Unsaved Config DS we wrote for IOS that compares the saved time and last config change time.  It _mostly_ works, but there are some annoyances.  One is uptime counter rollover, a general problem with timestamp comparisons.  The other is that IOS reports config changed the second you enter config mode even if you change nothing.