Use pageXOffset as fallback

IE9 & IE10 do not have the alias scrollX/Y
pageXOffset seems the original and standard property. See https://developer.mozilla.org/en-US/docs/Web/API/Window.scrollX

Maybe it could be used alone, not as a fallback for scrollX/Y
Add mouseout & mouseover events

Should fix issue #58
Merge pull request #56 from JSteunou/issue-55

Use pageXOffset as fallback
Merge pull request #59 from JSteunou/issue-58

Add mouseout & mouseover events
Merge pull request #5 from soulwire/master

Update from original master