Make pryrc load errors more useful.

lib/pry/pry_class.rb

@@ -69,7 +69,7 @@ class Pry
     begin
       toplevel_binding.eval(File.read(full_name), full_name) if File.exists?(full_name)
     rescue RescuableException => e
-      puts "Error loading #{file_name}: #{e}"
+      puts "Error loading #{file_name}: #{e}\n#{e.backtrace.first}"
     end
   end
 

spec/pry_spec.rb

@@ -390,7 +390,7 @@ describe Pry do
           end
 
           it "should output an error" do
-            @doing_it.call.should ==
+            @doing_it.call.split("\n").first.should ==
               "Error loading spec/fixtures/testrcbad: messin with ya"
           end
         end