i implemented eclass checking for some of the most common ones in the tree, 
but Zac didn't particularly care for the maintaining of lists of functions 
used by eclasses directly in repoman (due to the concern of them getting out 
of sync).

so the proposal is to utilize the existing eclass documentation markers to 
extract the complete list of functions provided by an eclass.  the upside is 
the metadata stays current, and we can scale better to all eclasses w/out 
requiring manual intervention.  the downside is that if people don't properly 
document their eclasses, repoman might throw false positives (warnings, not 
errors) about unused eclasses being inherited, and will miss throwing errors 
when functions are used but the respective eclasses aren't inherited.

however, i think that's a good hammer to throw at eclass maintainers to keep 
their documentation up-to-date and accurate.  any other opinions/feedback ?
-mike