Description of glyph header
============================

There are 7 parameters in each glyph header.

Par #1   Glyph nuamber
   Glyphs 32 to 127 and 160 to 255 are possible

Par #2   Orientation
   0 = portrait
   1 = landscape
   Value is always 0.

Par #3   Left offset
   All glyphs must have a character reference
   point.  The vertical and horizontal positions
   of this point correspond to the cursor
   position at print time.  The left offset is
   defined as the number of horizontal dots the
   reference point is left of the glyph cell.
   Value will depend on the glyph.

Par #4   Top offset
   The top offset is defined as the number of
   vertical dots the glyph cell extends above
   reference point.
   Value will depend on the glyph.

Par #5   Character Width
   Value = Width of glyph cell in horizontal dots.

Par #6   Character Height
   Value = Height of glyph cell in vertical dots.
     Note: we usually leave this at 0, and compute
     the value at load time, based on the number of
     data lines.

Par #7   Delta X   n
   Value = the horizontal distance the cursor
     should be moved after printing the font.
     This value is expressed as a 4x multiple
     of the number of dots to be moved.