[vtkusers] Change in DataArray to use operator new instead of malloc

[Utkarsh Ayachit]

vtkDataArrayTemplate used malloc()/free()/realloc() to allocate/free
memory. That has now been changed to use the C++ operators new and delete.

This change will affect those who have been passing an array to the
class to manage using SetArray() or SetVoidArray() with the "save"
argument set to "0". Earlier, it was assumed that the array was
allocated using malloc(), now it is required that the array is allocated
using new[].

Utkarsh.