* Extending template_matching tutorial with Java

* adding mask to java version of the tutorial

* adding the python toggle and code

* updating table of content

* adding py and java to table of content

* adding mask to python

* going back to markdown with duplicated text

* non duplicated text

1. Explain grayscale input still read as three channel
2. Fix typo
3. Add more details to image match explanation to include the use of masks

Also fixed some typos and code alignment
Also adapted tutorial CPP samples
Fixed some identation problems

These codes should be included into regular builds.