Add a return value to remove warning
Fix bug in error message in example AddSphereFromInput
Merge branch 'fix/warnings-accessible' into 'master'

Should remove build warnings regarding accessible not-initialized value

+1: haizhouW, Julien Lenoir, gsathyaseelan

Merged-on: https://www.assembla.com/code/OpenSurgSim/git/merge_requests/833993
Get rid of /n in std::cout (in Example/AddSphereFromInput and Framework/Timer.cpp)
Merge branch 'fix/bugExampleAddSphereFromInput' into 'master'

Fix bug in error msg in example AddSphereFromInput

Merged-on: https://www.assembla.com/code/OpenSurgSim/git/merge_requests/837383
Merge remote-tracking branch 'origin/master' into wip/Physics-Serialization
Specialize YAML::Convert<> for Physics classes

Specialize YAML::Convert<> for RigidRepresentationBaseState,
RigidRepresentationState, RigidRepresentationParameters.
Make RigidRepresentationBaseState serializable

1. Separate implementation from declaration.

2. Make RigidRepresentationBaseState inherit from Accessible.

3. Make pose in RigidRepresentationBaseState  serializable.

4. Add UnitTest for serialization of RigidRepresentationBaseState.
Make RigidRepresentationState serializable

1. Separate implementation from declaration.

2. Make linear and angular velocity in RigidRepresentationState
   serializable.

3. Add UnitTest for serialization of RigidRepresentationState.
Revise serialization of RigidRepresentationParameters

Customize copy constructor and copy assignment operator so that
RigidRepresentationParameters can be decoded as instance correctly.

Revise UnitTest accordingly.
Make RigidRepresentationbase serializable

1. Make 'InitialState' and 'InitialParameters' serializable

2. Use forward declaration in header file if possible, remove unused
   headers.

3. Add header file 'RigidRepresentationLocalization.h' in
   PhysicsmanagerStateTests.cpp in order to avoid compilation failure.