widl: Check that attributes applied to typedefs and fields are applicable and issue an error otherwise.

widl: Check that attributes applied to interfaces, functions and arguments are applicable and issue an error if not.

include: Add local to interfaces or functions that take a void * parameter and so aren't designed to work remotely.

The parameter for ITextPara::GetDuplicate should have two levels of 
indirection.

It is only accepted by MIDL as a synonym for pointer_default(unique), 
but it isn't a synonym in widl so remove it.

Reimplement NdrSimpleTypeUnmarshall using similar macros to
NdrBaseTypeUnmarshalling without buffer checks, due to
NdrSimpleTypeUnmarshall not doing any safety checks.

Use RegInstall instead of RegInstallA as RegInstallA isn't available in
some native versions of advpack commonly installed by programs.