Tidy up XD_HOME

* Revert to XD_HOME being a directory (no file: prefix)
* Keep classpath*/modules as an alternative module location
* Introduce extra optional indirection for everything under XD_HOME
(e.g. xd.data.home, xd.module.home, xd.ui.home, xd.config.home)
* Tested shell scripts in xd-*

Ensure SimpleModule copies profiles from parent Environment

Some people have been seeing spurious entries in Redis. This is
because a Module context would have been using the default
settings for transport and store. Now that the Environment is
passed down to child contexts it should be cleaner.