fixed dependency of stitching module on xfeatures2d module as optional
fixed the initModule_xfeatures2d function that was called in module stitching since it is in another namespace than the standard cv one.

new hysteresis

delete whitespaces

fix problem with mad24

Dynamic work group size

dynamic work group size

Fix problem with warnings

Fix some problems with border

Another one fix

Delete trailing whitespaces

some changes

fix problem with warning