* xdisp.c (display_text_line): Apply faces to characters according

* xdisp.c (display_text_line): Apply faces to characters according
	to overlays and text properties; use compute_char_face to figure out
	what face to use, and where a new face starts.
	* xterm.c (dumpglyphs): Use the upper bits of the glyphs to decide
	which frame face to use.  Call GLYPH_FOLLOW_ALIASES to make sure
	we're implementing the glyph table properly.  If we're not using
	the default or mode line face, call intern_face to find a display
	face for the frame face selected by the glyph code.  Implement
	underlining.  Remove the `font' argument; we have to derive this
	from the frame and face anyway.  Change all callers.
	* disptab.h (GLYPH_FOLLOW_ALIASES): New macro.