Cleanup registry.php.dist file

Cleanup registry.php.dist file

Format remains the same, so no need to alter current config file.  But
offers the following improvements:

Use one array to eliminate duplicative/confusing $this->applications[]
instances scattered throughout.

'status' no longer required; defaults to 'active'.

'fileroot' and 'webroot' no longer required; defaults to HORDE_BASE and
web auto-detection respectively.

Move web auto-detection into Horde_Registry.  If auto-detection doesn't
work for an admin, it makes more sense for them to just enter the proper
webroot rather than trying to tweak the detection function.
Additionally, registry.php can now be loaded multiple times in an access
- since the registry needs to be completely rebuilt for things like a
forced config change or langauge switch.  Thus, this prevents the need
for a function_exists() check.

Add optional variables to allow for definition of app fileroot/webroot
if different than Horde's.  Very useful for dev's - no need to hardcode
fileroot values for each application if using links.