Fix bug #314:

- remove most of the metaprogramming kung fu in MathFunctions.h (only keep functions that differs from the std)
- remove the overloads for array expression that were in the std namespace

test/sparselu.cpp

@@ -40,4 +40,4 @@ void test_sparselu()
   CALL_SUBTEST_2(test_sparselu_T<double>());
   CALL_SUBTEST_3(test_sparselu_T<std::complex<float> >()); 
   CALL_SUBTEST_4(test_sparselu_T<std::complex<double> >());
-}
+}