To resolve undefined "Mat_to_vector_KeyPoint" error

improved fix for java wrapper generator (gen_java.py) to avoid generation of java methods with duplicate signatures(v3)

Before:
    Ptr<Dictionary>((cv::aruco::Dictionary*)dictionary_nativeObj)
After:
    Ptr<cv::aruco::Dictionary>((cv::aruco::Dictionary*)dictionary_nativeObj)

* fix for feature2d java wrappers as described in this post: http://answers.opencv.org/question/101675/surfsift-java-wrapper-for-opencv-3xosx-1011/

* fix for feature2d java wrappers as described in this post: http://answers.opencv.org/question/101675/surfsift-java-wrapper-for-opencv-3xosx-1011/

* rollback of one change as requested (similar change already merged)

While generating Java JNI wrappers package names with an underscore (`_`) character where not properly escaped according to https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/design.html#resolving_native_method_names (see also: https://github.com/Itseez/opencv_contrib/issues/652).

This fix replaces all the occurrences of `_` with `_1` resulting in proper JNI method names.

* Adds the main features2d header to the parse list for the generator.
* Removes the manual definition of drawKeypoints and drawMatches since these are now included in the main header.
* Updates the generator to ignore SimpleBlobDetector, FlannBasedMatcher and DescriptorMatcher as these cause conflicts with the generator. This is okay since these were not previously included in the distribution anyway, so no harm is done.

 - cv2.UMat implemented - python thin wrapper for UMat
 - no implicit copy from GPU to Host done, resulting UMat can be passed to next function without overhead
 - cv2.UMat.get() - to fetch data to Host
 - new tests covers: ORB, BFMatcher, goodFeaturesToTrack, calcOpticalFlowPyrLK

fixing fourcc

Revert of "Merge pull request #4006 from sgjava:opencv-steve" (reverted from commit 47431840)

Revert of "Merge pull request #4014 from sgjava:opencv-sgjava" (reverted from commit 52fa55a7)

   (use "git reset HEAD <file>..." to unstage)

	modified:   highgui/include/opencv2/highgui/highgui_c.h
	modified:   highgui/src/cap_dshow.cpp
	modified:   java/generator/gen_java.py

The correction of the orthographic error in the enumeration constant
CAP_PROP_MONOCROME has been undone.

   (use "git reset HEAD <file>..." to unstage)

	modified:   modules/highgui/include/opencv2/highgui/highgui_c.h
	modified:   modules/highgui/src/cap_dshow.cpp
	modified:   modules/highgui/src/cap_pvapi.cpp
	modified:   modules/java/generator/gen_java.py

Änderungen in der PvAPI hinzugefügt.

   (use "git reset HEAD <file>..." to unstage)

	modified:   modules/java/generator/gen_java.py
	modified:   modules/videoio/include/opencv2/videoio.hpp
	modified:   modules/videoio/include/opencv2/videoio/videoio_c.h
	modified:   modules/videoio/src/cap_dshow.cpp
	modified:   modules/videoio/src/cap_pvapi.cpp

Following changes have been made:
1. Some minor bugs have been removed.
2. In the PvAPI module the option CAP_PROP_MONOCROME has been removed because
   this option does not make sense and causes an error if a color camera is used.
3. Instead the new option CAP_PROP_PVAPI_PIXELFORMAT has been added which allows
   to activate the different pixel formats (color modes) of an AVT camera.
4. Since there were two identical defines
   CAP_PROP_MONOCROME = 19
   CAP_PROP_MONOCHROME = 19
   which were also used in the other module DSHOW, the first one with an orthographic
   error has been removed in favor of the second one.

- wrapper support python3
- added wrapper log
- generating full name for nested namespaces and classes

- fixed lena.png extension
- fixed getTextSize wrapper
- added junit html report generation

- disabled xfeature2d dependency for java wrappers
- fixed java wrappers build after cmake rerun
- disabled opencv_ml tests temporarily
- fixed Imgproc usage in java tests