Revert "disable gpu Subtract_Array test:"

This reverts commit e91bf95d5832e87aa70240c50f0bf7fcc587e8c8.
Revert "disable gpu CvtColor.*2HSV tests:"

This reverts commit 952027a8536215a5e4308c79a59308c6b3426354.
fix epsilons for several gpu tests
Revert "disable CUDA generalized Hough Transform"

This reverts commit 33d42b740c6fe938b63a0b25c9ad51741aba48c3.
Merge pull request #2294 from jet47:fix-gpu-issues