remove fonts, do @sc differently and other things

Hi,

I am gonna try to address the last validation errors and change how some 
formatting is done. Please comment if you don't like my ideas.

* accronyms:
don't use font, just print the text as is.

* sc:
don't use latex2html even when l2h is true, instead enclose do like makeinfo 
--html (enclose in <small> capitalized text).

* smalldisplay smallexample:
font is forbidden in pre and pre is forbidden in font. Thus use style to make
it smaller. 
Is it compatible with earlier browser (ie will they ignore the style tag ?).

* in deff don't use <u> but <i>, as u is deprecated.

* menus:
menu comments are always in a preformatted style

If I don't get feedback, I will do these changes soon.

Pat