MSVC2013 property page to change the target architecture to simply "IA32"

(don't assume SSE support in target CPU).

src/build/target_ia32.props

+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ImportGroup Label="PropertySheets" />
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup>
+    <_PropertySheetDisplayName>Target IA32 (non-SSE) CPU</_PropertySheetDisplayName>
+  </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <EnableEnhancedInstructionSet>NoExtensions</EnableEnhancedInstructionSet>
+    </ClCompile>
+  </ItemDefinitionGroup>
+  <ItemGroup />
+</Project>
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