These patches modify the indentation implementation to use `<p

These patches modify the indentation implementation to use `<p
style=margin-left: n%>'.  Many thanks to Peter and Larry for
suggesting this solution.  Grohtml only uses tables for `.IP' and
related tags when the first operand has a short width.

Similarly, they modify all vertical space code.  By default, grohtml
sets up a style sheet which uses no vertical space between `table',
`pre', and `p' tags.  It forces spaces when it needs them using
`style="margin-top: 1em"'.

* src/devices/grohtml/html-table.cpp: Include `html-text.h'.
(html_table::emit_table_header, html_table::emit_new_row):
Rewritten.
(html_table::set_space): New function.
(html_indent::html_indent): Don't set `is_used'.
(html_indent::begin): Rewritten.
(html_indent::end): Remove code in function.

* src/devices/grohtml/html-table.h: Updated.
(html_table): Make `out' public.

* src/devices/grohtml/html-text.cpp (html_text::html_text):
Initialize `start_space' with FALSE.
(html_text::end_tag) <P_TAG, PRE_TAG>: Updated.
(html_text::issue_tag): Add argument to handle space style.
(html_text::start_tag) <P_TAG, PRE_TAG>: Updated.
(html_text::flush_text): Don't set `start_space'.
(html_text::push_para): Don't set `p->really_issued'.
(html_text::do_emittext): Updated.
(html_text::do_para): Add paremeter to handle space.
Update all callers.
(html_text::retrieve_para_space): New function.

* src/devices/grohtml/html-text.h (STYLE_VERTICAL_SPACE): New macro.
(tag_definition): Remove `really_issued'.
(html_text): Updated.

* src/devices/grohtml/post-html.cpp (html_printer): Add variables
`current_column' and `row_space'.
Update constructor.
(html_printer::emit_raw, html_printer::write_header,
html_printer::do_indent, html_printer::do_check_center,
html_printer::do_tab_ts): Handle vertical space.
(html_printer:do_tab_te, html_printer::do_end_para): Call
`remove_para_space'.
(html_printer::do_col): Rewritten.
(html_printer::flush_globs): Remove debugging code.
(html_printer::is_line_start): New function.
(html_printer::start_font): Use `is_line_start'.
(html_printer::writeHeadMetaStyle): New function.
(html_printer::do_file_components, html_printer::~html_printer):
Call `writeHeadMetaStyle'.

* tmac/www.tmac (www-handle-percent): New macro.
(MPIMG): Handle percent values for width and height parameters.
(DC): Updated.

* tmac/groff_www.man: Updated.