cudev is used for new device layer

This should allow many algorithms to take advantage of more parallelization
technologies.

This reverts commit fba72cb6, reversing
changes made to 02131ffb.

Made all STL usages explicit to be able automatically find all usages of
particular class or function.

removed test whether z is negative in gpu::solvePnpRansac (there is no need in this for tests passing)

reworked nearly all of the OpenCV tests (except for opencv_gpu tests) - they now use the Google Test engine.