Fix describe issues
Fix describe issues

Show nested describe names in test output, and also fix a problem where
describe-level tags were broken.

mpeterv/busted,ryanplusplus/busted,DorianGray/busted,o-lim/busted,istr/busted,Olivine-Labs/busted,xyliuke/busted,sobrinho/busted,leafo/busted,nehz/busted