Add debug logging

source/page.d

@@ -109,7 +109,13 @@ class Page {
 		string line;
 		while ((line = pandoc.stdout.readln()) !is null) {
 			result ~= line;
+			logf("Pandoc stdout: %s", line);
 		}
+
+		while ((line = pandoc.stderr.readln()) !is null) {
+			logf("Pandoc stderr: %s", line);
+		}
+
 		return result;
 	}