Update and clean up the Visual Studio 2017 project files

These were very shoddily put together!
It seems the person who made them never really tried building
the editors or the tests.

Also included here are a couple of minor source changes that are needed
to make the project files build.

proj/vs2017/Installer/Installer.vcxproj

@@ -74,7 +74,6 @@
     <ClCompile>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <SDLCheck>true</SDLCheck>
       <ConformanceMode>true</ConformanceMode>
     </ClCompile>
   </ItemDefinitionGroup>
@@ -82,7 +81,6 @@
     <ClCompile>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <SDLCheck>true</SDLCheck>
       <ConformanceMode>true</ConformanceMode>
     </ClCompile>
   </ItemDefinitionGroup>
@@ -92,7 +90,6 @@
       <Optimization>MaxSpeed</Optimization>
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
-      <SDLCheck>true</SDLCheck>
       <ConformanceMode>true</ConformanceMode>
     </ClCompile>
     <Link>
@@ -106,7 +103,6 @@
       <Optimization>MaxSpeed</Optimization>
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
-      <SDLCheck>true</SDLCheck>
       <ConformanceMode>true</ConformanceMode>
     </ClCompile>
     <Link>