Make hide_results_on_select option apply for deselecting as well

[VanTanev]

Summary

hide_results_on_select: false option currently applies only for selecting options. It should apply on deselect as well, as custom skinning of chosen can make use of it.

Please double-check that:

• All changes were made in CoffeeScript files, not JavaScript files.
• You used Grunt to build the JavaScript files and tested them locally.
• You've updated both the jQuery and Prototype versions.
• You haven't manually updated the version number in package.json.
• If necessary, you've updated the documentation. -
  I am unsure if this neccesitates a documentation change, as I think that this should have been the intended behavior of the option.

[cgatesman]

I believe this request is the same as what I'm looking for. To further explain, when using hide_results_on_select: false, it would be nice to be able to click on already selected items (which are currently greyed out) in order to unselect them (as if you clicked on the x of the .search-choice).

[VanTanev]

Updated to also not scroll the dropdown menu to top when hide_results_on_select: false.