Lots of raw pointers have been converted to boost::scoped_ptr to reduce
the number of 'delete's and the possibility of memory leaks.
Some pointers have been converted to references, to reduce the needless
checking for nullptrs, and so simplifying the code.
Also some #define-s have been converted to C++ constants or enumerations.

Change-Id: Ifbeb78f744bac7a96c8a446ff4db90dedf85fe26