[Dropdown] allowAdditions: Focus not returned to input box after clicking item

[eslachance]

I did not add a jsfiddle for this because it can be reproduced directly on the Examples page:
http://semantic-ui.com/modules/dropdown.html#tagging-and-user-additions

Typing in a partial search term in the Multiple box, then clicking on an existing term (for example, type in info then click Information Architecture) does not return the focus to the input box. This makes it impossible to rapidly add multiple tags simply by typing then clicking on each term.

Steps to reproduce:

1. Go to http://semantic-ui.com/modules/dropdown.html#tagging-and-user-additions
2. Enter info in the search box
3. In the drop-down, click Information Architecture

Result: The focus is not in the input box. Searching again requires clicking in the input box.

[jlukic]

#3790 fixed in next