Include reference to help-files for IDL generated by ActiveQt

The IDL generated by ActiveQt when building a server doesn't include any reasonable documentation (the metaobject doesn't support documentation for signals, slots or properties to be provided as part of the class declaration). However, IDL supports a helpfile(...) attribute for the type library:

[
uuid(...),
version(1.0),
helpfile("myactiveX.hlp"),
helpstring("myactiveX 1.0 Type Library")
]
library myactiveXLib
{
importlib("stdole32.tlb");
importlib("stdole2.tlb");
....
}

IDC could generate this helpfile() string based on a command line parameter which could in turn be provided through an entry in the .pro file.