msbuild: use default Project attrs

maybe it makes the xml less scary :D

Externals/cubeb/msvc/cubeb.vcxproj

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<Project>
   <Import Project="..\..\..\Source\VSProps\Base.Macros.props" />
   <Import Project="$(VSPropsDir)Base.Targets.props" />
   <PropertyGroup Label="Globals">

Externals/cubeb/msvc/cubeb.vcxproj.filters

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<Project>
   <ItemGroup>
     <ClInclude Include="..\include\cubeb\cubeb.h" />
     <ClInclude Include="..\src\cubeb_array_queue.h" />