Fixed a bug where the game wouldn't save
Removed unnecessary initGame function

and moved its contents into init
Minor formatting fix
Fixed some misleading property names

rows, columns, and boxes have plain arrays of jQuery objects, so they
shouldn’t begin with a $.
Re-added comment I mistakenly deleted

The shuffle method re-arranges some digits
Optimizations, mostly to getCell and getCells
Made populateGrid function accept non-given digits
Removed unnecessary updateConflicts call

The conflicts will only be updated once when restoring the game, which
may speed up the restore noticeably.
Removed unnecessary save attempt
Optimization to solver

This small change makes a big speed improvement.
Visual changes to buttons in difficulty popup

They are bigger and more spread out, which may help with touch devices.
Removed some unnecessary Underscore calls.
Tweak to generateRandomDigitHash method
Added a comment
Added method to find conflict cells in a digit hash

findConflicts now calls this method. Also removed some properties from the
plugin which are no longer necessary.
Removed test function

I am planning to come up with some real tests and put them in a
different file.
Refactored code that tests for win
Fixed a minor bug with moveIsValid

It would return false for a number that is on the grid, even if the
move was valid.
Minor refactoring of code involving peer cells
Slightly simplified findConflictCells method

Initially, I didn’t notice that _.pick can take an array of properties.