Use .closest() instead of .parents() because the latter will also reach parent elements of the plugin container

In other words, if the multiselect plugin is used inside an LI.container tag, it will eventually modify it which is not intended
Ignore intelliJ project file
Merge pull request #400 from kayhadrin/fix/avoid-changing-unrelatd-parent-elements

#375, #383: Avoid changing unrelated parent elements.