Add shiftRowsUp/shiftRowsDown methods

[igorinov]

These row shifting functions were created for an experimental implementation of fixed lag smoother based on Kalman filter.
The shift functions were optimized out of that filter implementation later, but they may be useful for some other projects.

[lessthanoptimal]

Over all looks good. One documentation comment. Could you remind me what the application is again?

[lessthanoptimal]

Could you mention what happens to the rows that are now unoccupied?

[igorinov]

Done.

[lessthanoptimal]

Could you also run ./gradlew spotlessApply it should fix the copyright issue and allow CI to pass. I think only one file should bechanged.

[igorinov]

Over all looks good. One documentation comment. Could you remind me what the application is again?

It was added for fixed lag and fixed interval smoother. Recently I optimized my smoother implementation to avoid shifts, but they could be useful in other projects.

[lessthanoptimal]

CI still isn't passing. Did you try running ./gradlew spotlessApply yet?

[igorinov]

FAILURE: Build failed with an exception.

* What went wrong:
Task 'spotlessApply' not found in root project 'ejml'.

[lessthanoptimal]

weird. Could you try this?

cd ejml
git fetch
git rebase origin/SNAPSHOT
./gradlew spotlessApply