Fix sudoku java

[tom-hg57]

Rebased and adapted to new Sudoku.java and SudokuJava.ipynb:

• Identify the exact puzzle number (third fix from Code fix in Sudoku solution validation + An enhancement to identify the exact puzzle number #143)
• Remove older version of Sudoku.java
• Remove java class files from repository
• Add missing sudokus1.txt, remove some unused example files
• Fix usage text and some typos in SudokuJava.ipynb
• Fix some more typos
• Remove older version of Jotto.ipynb (fixing case sensitive path for ipynb/Jotto.ipynb and ipynb/jotto.ipynb #131)
• Fix check that the listing of *.ipynb files matches the README.md file