renamed some recipes in prep for adding extension intro

diff --git a/lib/Moose/Cookbook/Extending/Recipe1.pod b/lib/Moose/Cookbook/Extending/Recipe3.pod
similarity index 100%
rename from lib/Moose/Cookbook/Extending/Recipe1.pod
rename to lib/Moose/Cookbook/Extending/Recipe3.pod

diff --git a/lib/Moose/Cookbook/Extending/Recipe2.pod b/lib/Moose/Cookbook/Extending/Recipe4.pod
similarity index 100%
rename from lib/Moose/Cookbook/Extending/Recipe2.pod
rename to lib/Moose/Cookbook/Extending/Recipe4.pod