HLSL: Namespaces don't appear to be supported

[dankbaker]

Not a high priority, but I thought I'd put an issue to track it anyway. Example shader:

namespace foo
{
cbuffer test
{
    float4 Val;
};
}
float4 main() : SV_POSITION
{
    return foo::Val;
}

[johnkslang]

Transferred to issue #362.