Fix to the matrix_exponential_rankN, to return the exact exponential for any higher dimensional square matrix
of shape [NE][NS][NM][NO][ND][X][X].
The fix was to the eye(X), to make the shape the same as the input shape.
Task #7807 (https://gna.org/task/index.php?7807): Speed-up of dispersion models for Clustered analysis.
Authored by: tlinnet 2014-06-19
Parent: [r24169]
Child: [r24171]
