add onSelectionChange and persist selectedRowIds across pages

[tim-phillips]

I've implemented an onSelectionChange callback that the user can use. I needed it for a project of mine and couldn't figure out how to get Griddle 1.0 working, so here are my changes.

A number of these changes are cosmetic, the formatting in the existing multiple selection code was pretty inconsistent.

I don't know why my .js files are so much longer than other peoples' changes, but this is what I got when I built with grunt.

Please let me know if you have any questions or issues with these commits.

[tim-phillips]

For reference: #125, #144, #151, #153, #175, #218, #230, #234

[ryanlanciaux]

Thanks so much - one of us will test it out a bit more and try to get things merged + published today / tomorrow.

[joellanciaux]

Thank you for putting this together! 👍

[tim-phillips]

You got it!

[nickwang14]

Is there documentation on how to implement this when using griddles? I don't see any references to checkboxes in the documentation.

Note: I saw current documentation is v0, does that mean these changes have been merged but not released?

[dahlbyk]

I never worked with Griddle 0.x, so I can't speak to this feature, but this appears to be part of v0.8.2 (#809).

As far as I know v1 doesn't have an equivalent feature.