Update README.md with 0.6 info
L.Control.Zoomslider.js : update _onSliderClick() function

Best use of L.DomEvent.getMousePosition() function.
Merge pull request #56 from freepius44/patch-1

L.Control.Zoomslider.js : update _onSliderClick() function
Touch: make the knob align correctly

Make the knob align correctly on touch devices. Please test.
Merge branch 'master' into 0.6