Merge pull request #20 from mikera/master

Use latest core.matrix
Correct determinant calculation.  Closes #21.
add travis configuration file.
Add QR decomposition function
Merge pull request #23 from hans/master

Add QR decomposition function.   Thanks @hans that's great !
Merge pull request #22 from daydreamt/master

Add a travis configuration file.
make Matrix and Vector Reversible
Merge pull request #26 from mikera/master

Update dependencies
Merge pull request #25 from farrellm/rseq

Make Matrix and Vector Reversible