* Adding threading in calibrate.py

* samples: update calibrate.py

It allows umat buffers used in net forward interface
Signed-off-by: Li Peng <peng.li@intel.com>

remove unused macros and half definition macros,
also remove unused ocl::Queue
Signed-off-by: Li Peng <peng.li@intel.com>

Prevents access data after the end of input buffer near 4K page boundaries

Tests are usually lauched from source directory, so additional unnecessary
files should be eliminated.

Alternative ways (command line):
- python -B ...
- PYTHONDONTWRITEBYTECODE=1 python ...

Usage example (bash):
$ OPENCV_PYTEST_FILTER=test_digits python test.py -v

getUMat()/getMat() calls are scope based. Results of these calls can't be
stored somewhere for future usage.