Add HashChangeEvent

See also https://github.com/scala-js/scala-js-dom/issues/53
Merge pull request #54 from tindzk/master

Element: Fix setAttribute()
Merge pull request #55 from tindzk/ticket53

Add HashChangeEvent
Add charCode method binding to KeyboardEvent
Merge pull request #56 from l15k4/charCode

Add charCode method binding to KeyboardEvent
Coordinates in object Touch can be fractional

Properties screenX/Y, clientX/Y and pageX/Y can be fractional.
It depends on device pixel ratio. For example if the pixel ratio
is 2.0 then values like 23.5 are possible
Merge pull request #57 from andrey-fomin/fractional-xy-in-touch

Coordinates in object Touch can be fractional
Change types of some methods in Document and Screen

- Method Document#elementFromPoint(x, y) takes arguments of type Double
   http://www.w3.org/TR/cssom-view/#extensions-to-the-document-interface
- Width and height properties of Screen has type Double
   http://www.w3.org/TR/cssom-view/#the-screen-interface
Merge pull request #58 from andrey-fomin/types-in-document-and-screen

Change types of some methods in Document and Screen