Support for shop on subsite mapped to domain (e.g. cloud mode)

[Jemt]

Additional work is required to support a shop running on a subsite that is mapped to a domain or subdomain. E.g.:

test.com => /var/www/smcms/sites/test
or
sub.test.com => /var/www/smcms/sites/test

The shopping extension will not work on Sitemagic Cloud until this has been resolved.

What needs to be done:

• Adjust vhost configurations (URL rewriting on SMCloud)
• Adjust extensions/SMShop/PSPI/Config.php. It is not currently able to determine the correct path to the configuration override file for a subsite running under a domain or sub domain. We probably need to dublicate logic from SMEnvironment since Config.php does not run in the context of Sitemagic.
• Make sure files called outside of Sitemagic's context works: /extensions/SMShop/PSPI/Config.php, /extensions/SMShop/PSPI/****/Callback.php, /data/PSPI/Config.php, /sites/*****/data/PSPI/Config.php).