Optional update for armadillo
Ambadillo was updated to the final stable 5.x release.
Some feature were completed and bugs fixed in version 5.600.2:
* Added .each_slice() for repeated matrix operations on each slice of a cube.
* Expanded .each_col() and .each_row() to handle out-of-place operations.
- Submitted by Atri Bhattacharya (badshah400)