Refactor/ssp-move-algorithm-to-DefaultExperiment

[markaren]

This PR moves the osp runtime annotation stuff inside DefaultExperiment where it belongs.
This also reduces the complexity of ssp_parser.cpp

I have also renamed osp:SimulationInformation to osp:Algorithm and removed the description tag.
osp:FixedStepMaster is renamed to osp:FixedStepAlgorithm

Old:

<ssd:Annotations>
      <ssc:Annotation type="org.open-simulation-platform">
        <osp:SimulationInformation>
          <osp:FixedStepMaster description="FixedStepAlgorithm" stepSize="1e-4"/>
        </osp:SimulationInformation>
      </ssc:Annotation>
  </ssd:Annotations>

New:

<ssd:DefaultExperiment>
        <ssd:Annotations>
            <ssc:Annotation type="com.opensimulationplatform">
                <osp:Algorithm>
                    <osp:FixedStepAlgorithm stepSize="1e-4"/>
                </osp:Algorithm>
            </ssc:Annotation>
        </ssd:Annotations>
  </ssd:DefaultExperiment>

It also adds a xsd.

[kyllingstad]

Sorry for leaving this hanging for so long. Mostly good, just some small change requests from my side. Also, I'd like a second opinion on the XSD change.

[eidekrist]

Apart from the Jenkins build (can be fixed by merging master into this) things look good from my point of view.

[markaren]

How about stepSize vs baseStepSize for fixedStep?

[kyllingstad]

Looks good now.

[markaren]

I'd like to get a verdict on stepSize vs baseStepSize for the osp:FixedStepAlgoritm element before finally merging this PR. IMO baseStepSize makes more sense.

[markaren]

If there is no objections by the end of the day I'll merge using baseStepSize

[kyllingstad]

I agree, baseStepSize has a clearer meaning than stepSize.