Add simple test for D-Bus configuration service
Configuration service debug
Version which passes test for Boolean and String properties
a draft of the configuration interfaces
Drop the necessity to define the SetDefault method

The configuration interfaces no longer must define SetDefault method.
The object created from a configuration interface is register with the
default interface (com.redhat.problems.configuration) which defines this
method.
Allow property elements to specify the configuration files

Each property can be loaded from a different file than others.
Add String Array properties support
Do not exit on invalid values
Fix tests
Remove property's option upon SetDefault() if the property has no default