Fix a compilation error when HAVE_CLAMDFFT is on.
Move legacy part of opencv_contrib to separate header
Drop old python interface
Drop old python samples and tests
Remove documentation for old python wrapper
Turn pyopencv_to and pyopencv_from into templates

This protects from unwanted implicit conversions between types at compile time.
use host data when DEVICE_MEM_UHP is set (the risk of vary align size is owned by users)
Fix arithm's substract mismatch caused by incomplete merge
Merge pull request #810 from pengx17:master_fix_ocl_tmflag
Merge pull request #813 from bitwangyaoyao:master_fix
Merge pull request #812 from bitwangyaoyao:master_uhp
Merge pull request #809 from taka-no-me:drop_python1
Merge remote-tracking branch 'upstream/master'