Adds fitEllipseDirect to imgproc: The Direct least square (Direct) method by Fitzgibbon1999.

New Tests are included for the methods.
fitEllipseAMS Tests
fitEllipseDirect Tests

Comparative examples are added to fitEllipse.cpp in Samples.

Added gradiantSize param into goodFeaturesToTrack API (#9618)

* Added gradiantSize param into goodFeaturesToTrack API

Removed hardcode value 3 in goodFeaturesToTrack API, and
added new param 'gradinatSize' in this API so that user can
pass any gradiant size as 3, 5 or 7.
Signed-off-by: Vipin Anand <anand.vipin@gmail.com>
Signed-off-by: Nilaykumar Patel<nilay.nilpat@gmail.com>
Signed-off-by: Prashanth Voora <prashanthx85@gmail.com>

* fixed compilation error for java test
Signed-off-by: Vipin Anand <anand.vipin@gmail.com>

* Modifying code for previous binary compatibility and fixing other warnings

fixed ABI break issue

resolved merged conflict

compilation error fix
Signed-off-by: Vipin Anand <anand.vipin@gmail.com>
Signed-off-by: Patel, Nilaykumar K <nilay.nilpat@gmail.com>

Update planar_tracking.cpp (#9686)

Add demo code for cv::reduce, cv::merge and cv::split.

* Adds cv::resizeWindow() overload taking a single cv::Size argument.

* Replaces copied documentaion with Doxygen @overload command.