Fix issue with the dropdown on mobile

[kevinbrink]

• In some circumstances, attempting to scroll within the dropdown on mobile
  would cause the dropdown to disappear immediately, making it impossible to use
  properly. In my particular case, I was re-styling the dropdowns inside a date picker (http://amsul.ca/pickadate.js/, because it offers a few required features that the materialize date picker doesn't) in order to use the materialize dropdowns.

[JulienMaille]

This works but won't close the dropdown.
I think you need to add this:
#2953

[kevinbrink]

@Nefast : Mind expounding a bit? In my tests, it seems to work fine, and closes the dropdown when I need it to. I see the commit you linked to, as well as the additional code added to that.

When do we want the dropdown to close that my commit doesn't allow for?

[JulienMaille]

Well, if you look at the manual example from a desktop computer, the dropdown will close whenever you click an item: http://materializecss.com/dropdown.html
With your patch it will break this behavio on both desktop and mobile (and fix the scrolling issue on mobile which is nice 👍 )

[kevinbrink]

Ah, ok, I see what you mean now. Our particular application only encountered that particular issue in one area of the app. I see it now though!

[soryy708]

@kevinbrink There are merge conflicts