Fix #1908: Issue 1908 jquery update

[badrmodoukh]

I have updated the jquery dependency
I tested using "npm install" and all seems to work fine from my end
I also ran "vagrant up" and loaded thimble and all worked fine

[Pomax]

This is a big update, and we need to basically check to make sure that things mentioned in http://developer.telerik.com/featured/whats-new-in-jquery-3/ won't affect us during all common Thimble tasks.

[humphd]

I feel somewhat ill-equipped to test this, as I haven't really followed jquery in a long time. I do note that there is this: https://jquery.com/upgrade-guide/3.0/#jquery-migrate-plugin @badrmodoukh, do you want to try running with that plugin to see what it reports? I don't think we use a lot of deep corners of jquery, but we do use it heavily.

It might be good to try doing everything from loading the app to starting something new, to publishing, to remixing, etc. Lots of corner cases to try.

[humphd]

Testing locally, I can't see any issues.