ROOTS

clarified types (again): 'a is canonical for 'class' (as alternative to 'locale'), 'b is common for Hindley-Milner examples;

src/Pure
src/FOL
src/HOL
src/ZF
src/CCL
src/CTT
src/Cube
src/FOLP
src/LCF
src/Sequents
src/Doc
src/Tools