Implement selectedMax feature

[SteveTheTechie]

The selectedMax option limits the number of selections to a maximum value. If the user attempts to check an additional selection in the multi-select, a warning message is shown in the button for 1 second.

This feature is very useful for the "select up to a maximum of x out of y available selections" use case. It implements a constraint approach.

An additional unit test has been also added for this feature.

NOTE: This PR follows PR #725 in succession.

[SteveTheTechie]

Will re-open later.

[SteveTheTechie]

Re-opening. Found the problem. ;-)

[SteveTheTechie]

There is a question of what to do with checkAll if a selectedMax constraint is in place.
Perhaps "Check All" cannot be shown or acted on if a constraint is in place.
This also may present some challenges w/ Flip All.

Perhaps any selections beyond the selectedMax limit are cleared?

BTW, I already use selectedMax (I call it maxSelected) constraint feature in my old code version that I am using in my web app.

I am just trying to make sure I "tidy it up" here if other people are going to be using it, also.

[mlh758]

Okay, I rebased your last branch to squash it down. That means the history is a little different now between these branches. Don't worry though, it's an easy fix! You might want to make a branch off this branch to test on the first time you do the rebase --onto command just in case.

git rebase --onto <target_branch, probably ehynds/version3> HEAD~2
Make sure your changes are still there and correct
git push -f <-- The force push let's you overwrite the remote branch with the new history

What this does is take 2 commits off your current branch and replays them on top of the target branch. It's essentially a simplified cherry pick since you're only pulling off the top.

[mlh758]

Sorry I didn't respond to your question sooner. I would say it would be best to disable select all when the selectedMax feature is enabled. I don't think it would make sense to trim the options list down, and just selecting the first x rows options wouldn't be helpful either.

[SteveTheTechie]

Ok I will tweak this a bit more in a subsequent PR to address the concerns.

[SteveTheTechie]

This code update is included in #728. I am not sure if you want me to just close this and let you just merge #728?

[mlh758]

Yeah if this is in 728 as well I'll just merge it all at once.