* Adding threading in calibrate.py

* samples: update calibrate.py

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.

HoughCircles rewritten (PR #7434 updated) (#10041)

* initial version of renewed HoughCircles done

* fixed compilation

* fixed SIMD ability & compilation warning

* fixed accumulator nonmax comparison

* common Mutex for all invokers

* nzLocal is std::vector

* nz is std::vector

* SSE2 -> SIMD128

* centers is now std::vector

* circles is std::vector

* estimateRadius updated

* accum calculation w/o mutex

* less deprecated code

* several bugs fixed

* back to mutex, TLS gathering doesn't work

* extra code removed

* little refactoring

* docs note updated

* a little speedup

* warning fixed

rename caffe.proto => opencv-caffe.proto

rename caffe.proto => opencv-caffe.proto

add a corresponding test