add get-info function to Pollen reader for better compatibility with DrRacket

reader-base.rkt

@@ -43,4 +43,8 @@
     (define reader-mode mode)
     (define custom-read-syntax (make-custom-read-syntax reader-mode))
     (define custom-read (make-custom-read custom-read-syntax))
-    (provide (rename-out [custom-read read] [custom-read-syntax read-syntax]))))
+    (define (get-info in mod line col pos)
+      (λ (key default)
+        (case key
+          [else default])))
+    (provide (rename-out [custom-read read] [custom-read-syntax read-syntax]) get-info)))