Fix issue Felix-815. Properties becomes optional by default. Unvalued properties are not published with the service reference until they receive a value. Setter methods are not called until properties receive a value Injected values in fields follow standard Java initialization (null for object and arrays, 0 for numeric types, false for boolean). Mandatory properties can be set with the 'mandatory' attribute (supported in XML and in the annotations). The core.xsd XML Schema is also modified to add the new attribute.
This improvement allows removing default value in properties (such as in the architecture handlers). Provides test about this new improvement
Fix issue Felix-816 The comparator attribute is now supported for any binding policy. Provides test about using custom comparator with any binding policy
Fix issue Felix-817 Solve an issue in the ServiceExporter when a service in unregistered twice (throws an IllegalStateException since a recent modification of the Felix framework).
Fix issue Felix-818 Implement the ServiceReferenceImpl compareTo method (method added in OSGi R4.1). This method reuse the same implementation as the Felix framework ServiceReferenceImpl method.