[Chicken-users] srfi-123 egg - generic accessor/modifier

[Diego]

I ported srfi-123 to chicken scheme a while ago, but I never actually requested 
it be added to egg-location. Would be nice to make it available to others, if 
it seems ok to everyone. 

I'm not actually sure I handled every part of it correctly - srfi-123 has 
support for data types that in chicken scheme are provided by other eggs, so I 
just went ahead and made those a requirement for this one (rather than some 
conditional checking if they're loaded?). Technically, they're not _required_ 
for this srfi to work.

​- Diego​