[pygccxml-development] Bug fix for noncopyable objects that are copyable

[Allen B. <al...@vr...>]

I have attached a patch that fixes a bug I ran into in pyplusplus.

The problem was that I have something that looks like this.

class Base
{
protected:
   Base(Base& r);
   Base();
}

class Derived : public Base
{
public:
   Derived();
   Derived(Derived& r);
}

As you can see in the code, the base class has a protected constructor.  
In my case this is fine because it is a pure virtual base class.  The 
problem was that when I tried to wrap Derived, pyplusplus thought is was 
noncopyable because Base didn't have a trivial copy (ie. public).  This 
led pyplusplus to introduce boost::noncopyable into the exposer 
generated.  This was a bug because as you can see the Derived class is 
actually quite copyable.

The patch fixes the is_noncopyable method in type_traits to understand 
that the base classes can have either a public or protected copy 
constructor.

I regenerated bindings for a couple of libraries using this code and it 
seems to work fine.

-Allen