Fix "Release" build configuration (project was application instead of DLL).
GetItemInfo(): Clarify we mean the pointer to the ITclHostControl object.

* previously the address of the containing struct was returned, which coincided
    with the ITclHostControl object address (first struct element)
IActiveScriptSite: Rename all method impls to IInterface_Method().

* AddRef --> IActiveScriptSite_AddRef(), etc.
* method implementations are static, so the name does not matter at all