Ruby 1.9 issue, must explicitly run to_s on the err object. Closes #14.

Signed-off-by: Nick Quaranto <nick@quaran.to>

lib/jekyll.rb

@@ -70,7 +70,7 @@ module Jekyll
       STDOUT.puts "Configuration from #{config_file}"
     rescue => err
       STDERR.puts "WARNING: Could not read configuration. Using defaults (and options)."
-      STDERR.puts "\t" + err
+      STDERR.puts "\t" + err.to_s
       config = {}
     end