Replace handle with full name

I believe Bram prefers people use their real names so he can more easily
find the various runtime file maintainers.
Remove unused comment syn regions

Besides the previous implementation being broken, simply allowing
(comment) forms to be highlighted as usual is actually quite useful
given the Clojure convention of keeping example code in a (comment) for
quick evaluation and testing.
Always print Clojure version with vim-syntax-keywords
Replace tabs with spaces