PFW: Virtual subsystems

BZ: 14587

- Added the possibility to declare parameters which have no real hardware
implementation. They are only intended to configure the hosting platform.
- A new subsystem type "Virtual" has been introduced to support those
hardwareless parameters.
- Virtual subsystems need no Mapping declaration in the structure
description

Change-Id: I44115f0dd0a26af74a544c6f08473b200aad94d3
Signed-off-by: Patrick Benavoli <patrickx.benavoli@intel.com>
Reviewed-on: http://android.intel.com:8080/25405
Reviewed-by: Barthes, FabienX <fabienx.barthes@intel.com>
Tested-by: Barthes, FabienX <fabienx.barthes@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>
diff --git a/parameter/StringParameter.h b/parameter/StringParameter.h
index 8ed1c5b..f536ceb 100644
--- a/parameter/StringParameter.h
+++ b/parameter/StringParameter.h
@@ -45,7 +45,7 @@
     // Type
     virtual Type getType() const;
 protected:
-    // Used for simulation only
+    // Used for simulation and virtual subsystems
     virtual void setDefaultValues(CParameterAccessContext& parameterAccessContext) const;
 
     // Actual value access