To Do

• Verify that randomly generated puzzles are solvable. Perhaps generate complete solved puzzle, then clear all but a given number of squares, leaving them as Givens.
• Implement event for RegionComplete
• Implement event for PuzzleComplete
• Implement loading region patterns (or whole puzzles) from a file

• Verify that NumGivens falls within a reasonable range.
• Verify that MaxDigit fits the Region constraints - for example, if a region has 9 squares but the MaxDigit is 8, thats invalid.