* docs/*: serious rewriting of the documentation

    * include/freetype/internal/ftobjs.h, src/base/ftobjs.c, src/bdf/bdfdrivr.c,
    src/pcf/pcfdriver.c, src/pfr/pfrsbit.c, src/sfnt/ttsbit.c,
    src/type42/t42objs.c, src/winfonts/winfnt.c: introduced three new functions
    to deal with glyph bitmaps within FT_GlyphSlot objects. these are:

      ft_glyphslot_free_bitmap
      ft_glyphslot_alloc_bitmap
      ft_glyphslot_set_bitmap

    these are much more convenient to use than managing the FT_GLYPH_OWN_BITMAP
    flag manually. the font drivers have been modified to use them as well.

    * src/cache/ftlru.c: fixed an invalid assertion check
24 files changed