Add bindPopup API to the Marker class

[mollymerp]

This PR introduces methods for using Popups in conjunction with Markers and is not-so-loosely based on Leaflet's API of the same name.

Also includes the first DOM tests in the gl-js unit test suite using jsdom. I had to make some changes to js/util/dom in order for the tests to complete without errors, but there might be other workarounds using jsdom that I'm not aware of.

Provides a fix for the problem of adding a Popupon a click event to a Marker with the current API -- the Popup is created and then immediately destroyed unless you have Popup.closeOnClick: false because the click event bubbles up to the map canvas. Related discussion at #2931

Checklist

• briefly describe the changes in this PR
• write tests for all new functionality
• document any changes or additions to public APIs
• post scores for all benchmarks on your branch and master
• do a quick sanity check on the debug page
• get a PR review 👍 / 👎

[jfirebaugh]

Let's make Popup the only type accepted by bindPopup, and remove options. This separates concerns:

• Popup is responsible for construction and configuration of the popup.
• bindPopup is responsible for linking it with a Marker. It doesn't need to pass through all functionality provided by Popup.

[mollymerp]

@lucaswoj copying from my response to your 'outdated' line comment:
I was having issues with the functions run by the tests failing because document + window weren't in scope. I refactored to use the jsdom-global module which provides a cleanup function that removes the created variables from the global scope and can be called when the tests are complete. Is this acceptable?

Otherwise we can take the approach that mapbox-gl-directions uses (browserify + smokestack + tap) but that would require some refactoring of the test suite.

[lucaswoj]

I put together a PR that removes all uses of browser globals in #3063. I vote that we merge this as-is, ship it in the release today, and tweak the Marker tests within #3063.

[jfirebaugh]

Instead of tracking state in _popupHandlersAdded, callremoveEventListener when the popup is removed. This will prevent memory leaks and unexpected behavior if the Marker continues to be used without a popup. You'll need to save the this-bound version of _openPopup, say by using util.bindAll(['_openPopup'], this), so that it can be passed to removeEventListener.