A new try to synchronize bitmap font access.

include/freetype/freetype.h (FT_Bitmap_Size): `height' is now
defined to return the baseline-to-baseline distance.  This was
already the value returned by the BDF and PCF drivers.

The `width' field now gives the average width.  I wasn't able to
find something better.  It should be taken as informative only.

New fields `size', `x_ppem', and `y_ppem'.

* src/pcf/pcfread.c (pcf_load_font): Updated to properly fill
FT_Bitmap_Size.
Do proper rounding and conversion from 72.27 to 72 points.

* src/bdf/bdfdrivr.c (BDF_Face_Init): Updated to properly fill
FT_Bitmap_Size.
Do proper rounding and conversion from 72.27 to 72 points.

* src/sfnt/sfobjs.c (sfnt_load_face): Updated to properly fill
FT_Bitmap_Size.

* src/winfonts/winfnt.c (FNT_Face_Init): Updated to properly fill
FT_Bitmap_Size.

Redesigning the FNT driver to return multiple faces, not multiple
strikes.  At least one font (app850.fon from WinME) contains
different FNT charmaps for its subfonts.  Consequently, the previous
design of having multiple bitmap strikes in a single font face fails
since we have only one charmap per face.

* include/freetype/internal/fnttypes.h (FNT_Size_Rec): Removed.
(FNT_FaceRec): Remove `num_fonts' field and replace `fonts' with
`font'.

* src/base/ftwinfnt.c (FT_Get_WinFNT_Header): Updated.

* src/winfonts/winfnt.c (fnt_font_load): Don't set pixel_width equal
to pixel_height.
(fnt_face_done_fonts): Removed.
(fnt_face_get_dll_fonts): Renamed to...
(fnt_face_get_dll_font): This.  Add second function argument to
select face index.
Updated to load just one subfont.
(fnt_font_done, FNT_Face_Done): Updated.
(FNT_Face_Init): Handle `face_index'.
Updated.
(FNT_Size_Set_Pixels): Simplified; similar to BDF and PCF, the
bitmap width is now ignored.
(FNT_Load_Glyph): Updated.
Fix glyph index computation.
(winfnt_driver_class): Updated.