DDSPSMCF2 — Useless ReaderQuery on DataReader read/take

The ReaderQuery class bundles together the read-state as well as potential read conditions. However the read-condition is not always present. This leads to code that needs to check all the time wether something is set or not, which is not only very elegant/efficient but it is also error prone

Resolution
---------------
Remove the ReaderQuery and let the read API deal, through proper operations overloads, with ReadState and potential ReadConditions. This way it will always be clear if a read/take is with a condition or not both for the client code and the DDS implementor.

The DataReader API has been updated to provide the proper read/take overloads and remove the useless ReaderQuery. The concept of a Selector has been introduced to orchestrate complex read/take operations requiring selection based on state, content and instance. The new API is orthogonal, simple and composable. Below an example usage of the selector API:

LoanedSamples<Foo> ls =
dr.select()
.instance(handle)
. content(query)
.take();

This example takes the samples matching the query q for the instance with given handle.