fix(keyboardSupport): Prevent losing focus when slider is rerendered

[ValentinH]

Fix #411

Broken demo: http://jsfiddle.net/nqbcL6k1/
Fixed demo: http://jsfiddle.net/pvtotaw2/

[ValentinH]

@dagerikhl Can I have your feedback pls?

[codecov-io]

Current coverage is 100% (diff: 100%)

Merging #415 into master will not change coverage

@@           master   #415   diff @@
====================================
  Files           1      1          
  Lines         854    862     +8   
  Methods         0      0          
  Messages        0      0          
  Branches        0      0          
====================================
+ Hits          854    862     +8   
  Misses          0      0          
  Partials        0      0          

Powered by Codecov. Last update 8af6174...e77d91a

[dagerikhl]

I can confirm that the proposed solution fixes the problem seamlessly, thanks a lot!
The issue seems to have completely vanished, and the fix is as far as I can see optimal.

In response to your comment on the issue: #411 (comment)

You are correct in that it did not completely lose focus. It still appeared focused, and kept the blue square focus-indicator, but it could not be moved by using keys until it was purposely deselected and reselected.

This was on Google Chrome 53.0.2785.116 m.

Once again, thanks for being so helpful!

[ValentinH]

Great, then I merge it and will bump a new version.