- replace tutorial links via docs.opencv.org
- remove link on OpenCV 2.4
- avoid links on outdated packages

Many of the Android samples rely on an options menu to work properly
but, at least on newer devices, the menu is permanently hidden by the
Android theme "Theme.NoTitleBar.Fullscreen", which means that most
of the examples were dysfunctional.

- drop hello-android sample

* Update core.hpp

* Update imgproc.hpp

* Update ImgprocTest.java

* Update CameraCalibrator.java

* Update OnCameraFrameRender.java

* Update FindContoursDemo.java

* Update IntroductionToSVMDemo.java

* Update NonLinearSVMsDemo.java

* Update IntroductionToPCADemo.java

* Update Smoothing.java

* Update MainActivity.java

* Update CalcBackProjectDemo1.java

* Update CornerSubPixDemo.java

* Update CornerDetectorDemo.java

* Update GoodFeaturesToTrackDemo.java

Implementation of bit-exact resize. Internal calls to linear resize updated to use bit-exact version. (#9468)

- eliminate CMake 3.5+ warnings
- removed usage of dropped "OPENCV_CAMERA_MODULES" variable
- partial support for Android NDK 11+

https://github.com/opencv/opencv/issues/7590

now it builds by the command:
`cmake.exe -Wno-dev -GNinja -DCMAKE_MAKE_PROGRAM="path\to\ninja\ninja.exe" -DCMAKE_TOOLCHAIN_FILE=../opencv3/platforms/android/android.toolchain.cmake -DANDROID_ABI="armeabi-v7a with NEON" -DANDROID_SDK_TARGET=21 -DANDROID_NATIVE_API_LEVEL=14 -DCMAKE_BUILD_WITH_INSTALL_RPATH=ON -DBUILD_ANDROID_EXAMPLES=ON -DINSTALL_ANDROID_EXAMPLES=ON -DWITH_OPENCL=YES -DANDROID_OPENCL_SDK=path\to\OpenCL ../opencv`

OPENCV_ANDROID_SDK - OpenCV Android SDK location (or OpenCV build dir)
Can be passed via ndk-build parameter or environment variable.

Camera and Camera2 preview is rendered via OpenGL textures and can be modified on CPU via C++ code. No OpenCL yet.