class PDF::Reader::CidWidths

A Hash-like object that wraps the array of glyph widths in a CID font and gives us a nice way to query it for specific widths.

there are two ways to calculate a cidfont_glyph_width, that are defined in Section 9.7.4.3 PDF 32000-1:2008 pp 271, the differences are remarked on below. because of these difference that may be contained within the same array, it is a bit difficult to parse this array.