allow custom label formatting via functions

[Fice]

This allows you to use another formatter than format.js or use functions like fromNow() like

    function formatter(date, scale) {
      moment(date).fromNow(); //gives you sth. like '4 days ago'
   }

Or you could do any integerbased axis by giving the timeline integers

var items = VisDataSet([{id: 0, content: 'item 0', start: 1, end: 300000}]);

and use a custom formater and get the integer back via date.getTime(). Now you would be able to do any integer based axis. So this should enable a workaround for #92

[josdejong]

Thanks for your PR Fice, we will have a look at it next Monday.

Until then, can you please re-do the pull request to the develop branch instead of master?

[josdejong]

This will be a nice improvement. A few things:

• I'm wondering if it't enough to pass the date and scale, you may also want to know the current step size. We could pass that as third parameter.
• Can you redo the PR to the develop branch?
• Can you update the docs to reflect this new feature?

[Fice]

I'm not at my dev machine atm, will do it as soon as I have some time (probably this weekend).

[mojoaxel]

@Fice I would like to merge this. It would be very nice if you would make the changes, pointed out by josdejong. You can just make the changes in your local branch Fice:labelFunctions and push them. All changes get updated here in the pull request. Thanks!

[mojoaxel]

closed with #2145