Added new signal interface using boost::signals2 signalParamChanged.
Exposed to Python as ParameterGrpPy.AttachManager() to monitor changes
to all parameters, sub groups under the referring group.
Added new attribute for ParameterGrp(Py) to query the Parent and Manager
of the referring group.
The FCGlobal.h can be included in a Global.h header file of an extension module.
The reason is that some IDEs (e.g. QtCreator) fails to detect the export/import macros when only defined in the PreCompiled.h files and thus raise a parser warning.
