* Make noncopyable constructor and destructor default

C++11 provides the functionality.
Defining empty functions cause all classes derived from noncopyable
to be non-trivially constructible and non-trivially destructible.

For example, matrix with compile-time layout by definition does not
require an explicit destructor and should be trivially destructible
; however, deriving from noncopyable makes it non-trivially
destrutible. This also affects vector<T, 2> and vector<T, 3>.

* Delete array2d copy constructor and assignment operators