Merge 2.4 into master

Original pull requests:

* #2026 from pemmanuelviel:giveFurthestPoint
* #2400 from RJ2:Bugfix_2
* #2423 from RJ2:bugfix_5
* #2446 from asmorkalov:ocv_implicit_cuda_control
* #2449 from asmorkalov:cuda_abs_path_fix
* #2454 from apavlenko:2.4_haar_extend
* #2456 from kurodash:pr_use_cvAlloc
* #2458 from asmorkalov:android_cmake_opencv_modules_suffix
* #2460 from berak:b_3598_24
* #2473 from euphrat:mog2_weight_bugfix
* #2488 from Nerei:minor_doc
* #2490 from ilya-lavrenov:ocl_sep_filters
* #2501 from asmorkalov:android_native_camera_qualcomm
* #2504 from asmorkalov:android_camera_locks_24
* #2510 from asmorkalov:android_cuda_filter_fix
* #2511 from apavlenko:2.4_fix_perf_nonfree
* #2513 from asmorkalov:ocv_cuda_link_revert
* #2514 from asmorkalov:android_two_libs_cuda
* #2517 from ilya-lavrenov:fix