new egg: SRFI 278

[Peter McGoron via Chicken-users]

This egg implements complex inverse hyperbolic functions with the 
correct behavior near poles and branch cuts, along with some other misc. 
procedures.

release-info: 
https://files.mcgoron.com/chicken/srfi-278-egg/srfi-278.release-info
docs: https://wiki.call-cc.org/eggref/6/srfi-278
-- Peter McGoron