port type 1 lexer from pdf box and add test data

src/UglyToad.PdfPig.Tests/Integration/LaTexTests.cs

@@ -28,6 +28,17 @@
             }
         }
 
+        [Fact]
+        public void LettersHaveHeight()
+        {
+            using (var document = PdfDocument.Open(GetFilename()))
+            {
+                var page = document.GetPage(1);
+
+                Assert.NotEqual(0, page.Letters[0].GlyphRectangle.Height);
+            }
+        }
+
         [Fact]
         public void HasCorrectNumberOfPages()
         {