PFW: Parameter adaptation (platform interface)

BZ: 15069

Adaptation nodes have been added to integer parameter types in the structural
description.
They all convert values between a platform value and the actual parameter
value.
When a conversion node affects the definition of an integer type parameter,
its interface type becomes "double" (instead of integer).
For now only linear adaptation type is supported.

Linear adaptation:
=================
Linear adaptation nodes consists of the following attributes:
- slope numerator (double, default = 1)
- slope denominator (double, defult = 1)
- offset (signed integer, default = 0)
Conversions from user (platform) values to blackboard are done the follwing
way:
blackboard_value = user_value * slope_numerator / slope_denominator + offset

Change-Id: I00abe9ba5961d8e541b616225531bbc7c8b465b0
Signed-off-by: Patrick Benavoli <patrickx.benavoli@intel.com>
Reviewed-on: http://android.intel.com:8080/25407
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/Element.cpp b/parameter/Element.cpp
index 4e939c0..8981ba9 100644
--- a/parameter/Element.cpp
+++ b/parameter/Element.cpp
@@ -184,6 +184,15 @@
     return ostr.str();
 }
 
+string CElement::toString(double dValue)
+{
+    ostringstream ostr;
+
+    ostr << dValue;
+
+    return ostr.str();
+}
+
 // Content dumping
 void CElement::logValue(string& strValue, CErrorContext& errorContext) const
 {