Various fixes/improvements to the the extras/csrf_migration_helper.py script

- Fixed various bugs/oddities with command line parsing
- Find 'include' tags that use single quotes
- Fixed for new style TEMPLATE_LOADERS setting
- Don't silently ignore non-existent paths
- Removed Python-2.3-ism
- Removed an unnecessary loop



git-svn-id: http://code.djangoproject.com/svn/django/trunk@12267 bcc190cf-cafb-0310-a4f2-bffc1f526a37