[Slider] fix appearance

[KapJI]

I found several issues with Slider appearance:

1. When slider is at 0% the track overflows from the right.
2. After moving slider to 0% sometimes handle has black border because of overlapping border styles.
3. Spacing around disabled handle is relative and equal to 1% of width, but it should be equal to 2px.
4. Incorrect cursor and handle size when 0% and disabled.
5. No FocusRipple at 0%.
6. Incorrect handle size on click, 24px instead of 18px.
7. Transition to 0% when active.

This should fix all of them, but doesn't fix _setRippleSize() bug from #1451.
I used behavior and dimensions of sliders from https://www.google.com/design/spec/components/sliders.html
Tested on the latest stable Chrome, Firefox and Safari on OS X and on Chrome for Android.

[hai-cea]

@KapJI Can you rebase please?

[KapJI]

Done.

[Kagami]

Does this PR fix the following 2 bugs? Or should I create separate issues for them?

[KapJI]

In first case it changes how handle looks at 0% to
In second case I see two bugs: track shaking and black border of handle in the end. This PR fixes both.

[Kagami]

Great, thanks!

[Kagami]

I built your branch and can confirm: now both issues are fixed. 👍 for merging this.

The only minor thing that I've found is that slider stays focused after dragging. I guess this is correct behavior?

[KapJI]

I didn't change this behavior and I think that it is correct.

[hai-cea]

Thanks @KapJI @Kagami