* common/DynamicProperty.h, common/DynamicProperty_impl.h:
Add a second dynamic property template which can wrap any
property class, not just instances of Property<>.
* server/CorePropertyManager.cpp: Install a property factory for
COORDS, to handle the coordinates in a line.
* common/DynamicProperty.cpp, common/PropertyFactory.cpp: Remove
unnecessary template instanciations.
* common/DynamicProperty.cpp, common/DynamicProperty.h,
common/DynamicProperty_impl.h: New property class for handling
properties or attributes added on the fly which need to store the
value.
* common/PropertyFactory.cpp, common/PropertyFactory_impl.h,
server/CorePropertyManager.cpp: Use DynamicProperty in the
property factories for properties created on the fly.
