* OpenCV4Tegra/ is no longer relevant.
* We should only ignore the particular refman.rst that we generate.

removed test for double since not all platforms support double, thus the sanity check cannot pass on all the platforms.

include() doesn't create a variable scope, so the settings of
CMAKE_MODULE_PATH and CMAKE_FIND_ROOT_PATH_MODE_* were polluting
everything included after OpenCVDetectCUDA.cmake.

Also, FindCUDA includes FindPackageHandleStandardArgs, which includes
CMakeParseArguments, which causes warnings related to policy CMP0017.
Setting it to NEW seems safe enough.