Fix xfeatures2d dependencies
Support of bioinspired contrib module wrapping

- added java wrapper
- disabled python wrapper
Java wrappers now support nested namespaces and classes

- wrapper support python3
- added wrapper log
- generating full name for nested namespaces and classes
Neon optimization of cv::sum
Merge pull request #3239 from mshabunin:xfeatures2d_fix
Neon optimization of cv::convertScaleAbs
Merge pull request #3248 from ilya-lavrenov:arm_sum
Adding division operators to `Point_` class.

Performs element-wise division.
Adding element-wise division operators to Point3_ class.
Updating documentation to reflect division operations.
Optimize OpenCL version function BackgroundSubstractionMOG2
Merge pull request #3250 from ilya-lavrenov:neon_convert_scale_abs
Fixed GStreamer encoding pipeline frame drop for most cases.

For several muxers and encoders GStreamer still drops the last frame.
Merge pull request #3252 from GravityJack:point-division
Fixed compatibility with GStreamer 1.x.
More accurate selection of color space conversion element for GStreamer 1.x
Merge pull request #3253 from asmorkalov:ocv_gstreamer2
Correction of the integer data treated as floating point data bug, already corrected in the 2.4 branch.
Neon optimization of Mat::convertTo
Neon optimization of cv::scaleAdd (CV_32F)