Testing result of bwdtrans operator

With !4 (merged) we have a unit test structure around the StdMat backward transform implementation. However the "test" actually doesn't test the correctness of the result.

Boost.Test provides macros in order to test collections. Couple of options:

1. Use the default overloaded comparison operator - maybe something like

BOOST_TEST(fixt_out.toArray() == expected_out)

if Nektar::Array defines a comparison operator? Could also write a comparison for Field directly.

2. Use the boost::test_tools::per_element manipulator. Would rely on a Field to implement a forward iterator (or its Nektar::Array) representation.

BOOST_TEST(fixt_out, expected_out, boost::test_tools::per_element())

closed