removed previously deleted RtError.h from visual studio project

msw/rtmidilib.vcxproj

@@ -73,7 +73,6 @@
     <ClCompile Include="..\RtMidi.cpp" />
   </ItemGroup>
   <ItemGroup>
-    <ClInclude Include="..\RtError.h" />
     <ClInclude Include="..\RtMidi.h" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />

msw/rtmidilib.vcxproj.filters

@@ -20,9 +20,6 @@
     </ClCompile>
   </ItemGroup>
   <ItemGroup>
-    <ClInclude Include="..\RtError.h">
-      <Filter>Header Files</Filter>
-    </ClInclude>
     <ClInclude Include="..\RtMidi.h">
       <Filter>Header Files</Filter>
     </ClInclude>