* tmac/an-old.tmac (SH, SS, TP, IP, HP, TS): Protect .sp with .br

* tmac/an-old.tmac (SH, SS, TP, IP, HP, TS): Protect .sp with .br
so that it survives the implicit new-page trap.

* src/roff/troff/node.cc: Fix the changes from 2002-10-23.
(troff_output_file::set_font): Call flush_tbuf if necessary.
(troff_output_file::fill_color, troff_output_file::glyph_color): Call
flush_tbuf and do_motion only if necessary.
(troff_output_file::start_special,
troff_output_file::put_char_width, troff_output_file::put_char,
troff_output_file::draw): Updated.
(word_space_node::tprint, space_node::tprint, hmotion_node::tprint,
vmotion_node::tprint): Undo change 2002-10-23.