New matrix methods
Added messages to asserts in matrix functions
Added new iterator implementation (minor cosmetic changes)
Merge pull request #105 from pakozm/iterator

Added new iterator implementation (minor cosmetic changes)
Improved print in matrix
changes in matrix print
More matrix print
Minor change in matrix __call metamethod, allowing to specify m({},4) using {} as sinonym of ':'
Solved bug
Added squeeze method in other matrix flavours
Added squeeze method in other matrix flavours, solved problem in fill call
Solved problems with oop-iter
Merge pull request #104 from pakozm/stats

New matrix stats methods, and new print method