Report error, but don’t fatally stop if pygments has error. Return original string. (+1 squashed commit)

Squashed commits:
[849a7af] if highlighting doesn’t work, just return original string

helpers/pygments.go

@@ -38,7 +38,7 @@ func Highlight(code string, lexer string) string {
 
     if err := cmd.Run(); err != nil {
         log.Print(stderr.String())
-		log.Fatal(err)
+        return code
     }
 
     return out.String()