VariantCopy does not need to check the return of VariantClear.
VariantCopyInd now copies VT_UNKNOWN and VT_DISPATCH too.
VarCmp handles VT_BOOL.
VarFormat handles VT_BSTR.
coerce_array fixed for VT_ARRAY|VT_UI1 -> VT_BSTR and VT_ARRAY|x ->
VT_SAFEARRAY cases.
VarCat tries to coerce types into VT_BSTR to do cat.