Add EnableUnamangedDebugging=true default to csproj

* Since RenderDoc is heavily mixed .NET/C++ code, regardless of any
  disadvantages this option is practically required (e.g. if building in
  profile, the first error message or assert will take the program down
  as the breakpoint won't get caught).
* In the UI, enabling this option will always go into csproj.user, but
  in fact the option works fine if you manually put it into the csproj,
  which means this will be the default for all new clones. Yay!

renderdocui/renderdocui.csproj

@@ -29,6 +29,7 @@
     <IsWebBootstrapper>false</IsWebBootstrapper>
     <UseApplicationTrust>false</UseApplicationTrust>
     <BootstrapperEnabled>true</BootstrapperEnabled>
+    <EnableUnmanagedDebugging>true</EnableUnmanagedDebugging>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|x86' ">
     <PlatformTarget>x86</PlatformTarget>