Don't strdup() font name or color. Inserting the font into the dictionary
will do this now.
Replace dupFont() with insertion into font dictionary; remove unnecessary strdup()'s
as these will be done in the dictionary if necessary, and do a simple pointer
assignment. Note that if we want to use reference counting, we will
have to replace the font pointer assignment with a dup function.
Remove unnecessary variable in size_html_txt as the textfont_t structure has
these others as subfields; since we replace the font in size_html_txt, make sure
it gets the earlier color information; make sure font used in emit_html_txt gets
the necessary flags.