DDS — DDS ISSUE# 30] Setting of default qos on factories

Ref-?? Setting_default_qos_on_factories

The specification provides a way to create Entities with QoS by
explicitly providing the QoS when the entity is created.

In some cases it would be desirable to provide a pattern such that
many entities can be easily created with the same QoS without the
application explicitly. Thst way the management of the Qos can be
"centralized" in few modules in the application logic

**PROPOSAL**

Add the following operations:

DomainParticipant::set_default_publisher_qos(),
DomainParticipant::get_default_publisher_qos(),
DomainParticipant::set_default_subscriber_qos(),
DomainParticipant::get_default_subscriber_qos(),
Publisher::set_default_datawriter_qos(),
Publisher::get_default_datawriter_qos(),
Subscriber::set_default_datawriter_qos(),
Subscriber::get_default_datawriter_qos().

This allows the application to set a default QoS for the entities that
the factory will create, and then explicitly use that QoS to create
the entities.

Furthermore specify that if the set_default_xxx_qos operations are not
called then the get_default_xxx_qos will return the defaults specified
in section 2.1.3

see below