* src/roff/troff/column.cpp (vjustify_node::copy): Updated.

* src/roff/troff/column.cpp (vjustify_node::copy): Updated.

* src/roff/troff/div.h: Include `mtsm.h'.
(diversion): New variables `any_chars_added', `needs_push',
`saved_seen_break', `saved_seen_space', `saved_seen_eol',
`saved_suppress_next_eol', `modified_tag'.
New virtual member function `is_diversion'.  Update all descendants.

* src/roff/troff/div.cpp (diversion::diversion,
macro_diversion::macro_diversion): Updated.
(do_divert): Handle `seen_break', `seen_space', `seen_eol',
`suppress_next_eol'.
(top_level_diversion::space): Handle `curenv->seen_space'.
(page_offset): Update tag handling.
(space_request, blank_line, flush_output): Don't call `add_html_tag'.

* src/roff/troff/env.h (environment): Make `tabs' public.
Remove `ignore_next_eol', `emitted_node'.
Update `output_line', `output'.
New variables `seen_space', `seen_eol', `suppress_next_eol',
`seen_break'.
New member functions `construct_state', `make_tag',
`construct_format_state, `construct_new_line_state,
`dump_troff_state'.
Remove `add_html_tag', `make_html_tag'.

* src/roff/troff/env.cpp: New externs `suppress_push',
`get_diversion_state', `global_diverted_space'.
(pending_output_line): New variable `was_centered'.
Update constructor and all callers.
(pending_output_line::output): Call `curenv->construct_format_state'.
(environment::environment, environment::copy): Updated.
(environment::output): Handle `was_centered'.
(environment::add_char): Handle construct and diversion state.
(environment::add_node): Handle construct state.
(environment::newline): Handle `was_centered'.
(environment::output_line): Updated.
(environment::possibly_break_line): Updated.
Update tag handling.
(environment::add_html_tag): Replaced with...
(environment::make_tag): New function.
(environment::add_html_tag_tabs, environment::make_html_tag): Removed.
(environment::dump_troff_state): New debugging function.
(environment::construct_state, environment::construct_format_state,
environment::construct_new_line_state): New functions.
(environment::do_break): Updated.
Handle `global_diverted_space'.
(environment::handle_tag): Update tag handling.
(point_size, fill, do_break_request): Don't call `add_html_tag'.
(no_fill): Don't call `add_html_tag'.
Set `suppress_next_eol'.
(center, right_justify, line_length, indent, temporary_indent,
set_tabs):
Update tag handling.

* src/roff/troff/input.cpp: Don't include `stringclass.h'.
(input_iterator): New variables `is_diversion', `diversion_state'.
Update constructors.
(input_stack): New member functions `get_div_level',
`get_diversion_state', `check_end_diversion'.
New variables `div_level', `diversion_state'.  Initialize them.
(suppress_push, global_diverted_space): New global variables.
(input_stack::finish_get, input_stack::finish_peek,
input_stack::remove_boundary, input_stack::end_file,
input_stack::clear, input_stack::pop_macro): Call
`check_end_diversion'.
(input_stack::push): Handle `div_level' and `diversion_state'.
(get_diversion_state): New function.
(diverted_space_node::reread): Handle `global_diverted_space'.
(macro::macro): Update constructors.
(macro::is_diversion): New function.
(macro::operator=): Set `is_a_diversion'.
(string_iterator): New member function `is_diversion'.
(string_iterator::string_iterator): Update constructors.
(string_iterator::fill): Set `div_nest_level'.
(macro_iterator): New member function `is_diversion'.
(do_if_request): Handle `suppress_push'.
(tag, taga): New functions.
(init_input_requests): Add `tag' and `taga' requests.