add charset interface, create class to store cff font data. add the command logic for type 2 charstrings #6

src/UglyToad.PdfPig/Fonts/CompactFontFormat/Charsets/CompactFontFormatFormat2Charset.cs

@@ -0,0 +1,15 @@
+namespace UglyToad.PdfPig.Fonts.CompactFontFormat.Charsets
+{
+    using System.Collections.Generic;
+
+    /// <summary>
+    /// A Charset from a Compact Font Format font file best for fonts with a large number of well ordered string ids.
+    /// </summary>
+    internal class CompactFontFormatFormat2Charset : CompactFontFormatCharset
+    {
+        public CompactFontFormatFormat2Charset(IReadOnlyList<(int glyphId, int stringId, string name)> data)
+            : base(data)
+        {
+        }
+    }
+}