* Added performance tests for hal::norm functions

* Added sum of absolute differences intrinsic

* norm implementation updated to use wide universal intrinsics

* improve and fix v_reduce_sad on VSX

Add URLs, harmonise formatting, and fix parse error in bibliography (#13228)

* Fixed parse error in bibliography

* Removed extra curly braces

* harmonized whitespace

* changed organisation -> publisher where appropriate. Organisation is intended as the author's organisation, not the publishing.

* harmonized capitalisation and whitespace

* Add links to about 1/3 of references

created from RAW memory buffers (without proper lifetime management)

- don't require "OPENCV_PYTHON{2,3}_INSTALL_PATH" if OPENCV_SKIP_PYTHON_LOADER=ON
- avoid unnecessary relative paths in generated config-X.Y.py

Reduce input size for OpenPose tests

introduced by commit 4e629000