Stretch functional tests (#4154)

* stretch updates

* pull request changes

* modified setoutputcube to remove seg fault

* merge with dev + fixed bug

* updating test files

* modified stretch app

* updated mvix

* modified setoutputcube functions with null ui parameter

* modified stretch test and reverted changes involving setoutputcube

* modified setoutputcube function call

* made new setoutputcube for stretch

* added +1 back to user interface, removed duplicate test

* pull request changes

Co-authored-by: Kelvin <kelvinrr@icloud.com>