Shortened u.jel into u.j

I questioned whether to do this or not, but decided that the terseness
it enabled in the creation of nested html via javascript was worth the
obfuscation.  The idea is that u is for util for utility functions and
that j is for jel for jelement for jquery wrapped html element.
Normally, I prepent a jquery wrapped element with the letter 'j' and so,
since this function creates arbitrary elements, the prepend is the
onlypend.