[Enhancement] Offer more functionality for command-line processing

[leogott]

I'd like to use this app to filter and rate sudokus not only by peak difficulty, but also by other metrics to compare them against.

For example I'd like to process a list of sudokus and 1) return formatted output only for sudokus with SE-Rating >=3 2) for each print number of given digits 3) for each print number of digits after applying certain techniques as often as possible 4) for each list steps requiring techniques more difficult than e.g. Hidden Single

I'm certain most of these could be implemented easily, and I'm confident I could do it myself, but maybe some of these are already implemented?

[1to9only]

4. for each list steps requiring techniques more difficult than e.g. Hidden Single

In the original SudokuExplainer (by Nicolas Juillerat), there used to be Tester.java that can be called from the command line - It does similar to what the GUI->Tools->Analyze does.

Example command line (for original SE):

java.exe -cp SudokuExplainer.jar diuf.sudoku.test.Tester puzzles.txt output.log

Example output.log (from my modified SE):

Analyzing Sudoku #1
007100000041020000320009000500000800010070060009600005004300089090040670000002100
54 x Hidden Single (1.0-1.5)
1 x Direct Hidden Pair (2.0)
3 x Claiming (2.8)
1 x Hidden Pair (3.4)
1 x Naked Triplet (3.6)
1 x Swordfish (3.8)
1 x Hidden Quad (5.4)

Analyzing Sudoku #2
...

Tester.java has been removed from this version of SE.