niflib: project file fix (contributed by thephoenyx, see issue #2868260)

niflib.vcproj

@@ -593,6 +593,10 @@
 			Filter="cpp;c;cxx;def;odl;idl;hpj;bat;asm;asmx"
 			UniqueIdentifier="{4FC737F1-C7A5-4376-A066-2A32D752A2FF}"
 			>
+			<File
+				RelativePath=".\src\obj\BSMultiBoundData.cpp"
+				>
+			</File>
 			<File
 				RelativePath=".\src\Inertia.cpp"
 				>
@@ -2311,6 +2315,10 @@
 			Filter="h;hpp;hxx;hm;inl;inc;xsd"
 			UniqueIdentifier="{93995380-89BD-4b04-88EB-625FBE52EBFB}"
 			>
+			<File
+				RelativePath=".\include\obj\BSMultiBoundData.h"
+				>
+			</File>
 			<File
 				RelativePath=".\include\ComplexShape.h"
 				>