Rework ring's prelim to be ternaryComparisons and moved to src/sort

Addressing github issue #343, which is to use one base comparison
result type for what happens in both src/ring and src/enumfset.

Make more build-related cleanups

Consistently use dehyphenated version of name to stand as
kernelid (i.e., "expk", "stdknl", "otknl", rather than anything with
leading hyphens). This requires change to Holmakefiles that wanted to
build OpenTheory articles when being executed under otknl.

Also make

build cleanAll

clean in all directories, not just those belonging to stdknl.

Add hol-sort OpenTheory package