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.