CPack IFW generator updates:
- Group now can have script;
- Root package (for monolithic or one package installers) can be
configured from group.
CMake updates:
- Native installation (no Unspecified component).
Split the monolithic cmCPackIFWGenerator source into three parts:
cmCPackIFWGenerator, cmCPackIFWInstaller, and cmCPackIFWPackage
to isolate the implementations somewhat.
Add a COMMON option to the cpack_ifw_configure_component command to make
the data component common to its parent group.
Change the default packaging method to ONE_PACKAGE_PER_COMPONENT.
This is not incompatible because the CPack IFW generator has not
yet been in a release.