#55 move support for images to page and add inline images

support both xobject and inline images. adds unsupported filters so that exceptions are only thrown when accessing lazily evaluated image.bytes property rather than when opening the page.

treat all warnings as errors.

src/UglyToad.PdfPig/PdfDocument.cs

@@ -220,6 +220,7 @@
         {
             try
             {
+                pdfScanner.Dispose();
                 inputBytes.Dispose();
             }
             catch (Exception ex)