Hack to use the std::array support for boost::array.
Is limited as it currently exposes some 'using' bugs in SWIG.
For example, the type system fails to see that pointers to std::array
and pointers to boost::array are the same.
This approach saves having to maintain separate boost::array support.
The 'using' bug ought to be fixed, otherwise separate boost_array.i
files could be easily made from the std_array.i files.
