Draft: Add ld+memAlign to ShortMatrix+misc(last NDEBUG,...)

A partial implementation of the “leading dimension” concept in the ShortMatrixBase class hierarchy.

Only the ld member has been added. A full transition to this concept is not currently planned. Given the way the library is currently implemented and tested, a full implementation of the “ld” concept has shown that there is a gain in object creation but a bigger loss in access to matrix components.

Therefore, only the 'ld' calculation is performed for the ShortMatrix instance, and the memAlign method provides this information. The pointer vector ‘r’ is retained. However, when combined with the 'raw' method, this information ('ld') allows for efficient memory traversal by bypassing the use of ‘r’.