Updated code to work with GWT 2.6.1

Updated code for GWT 2.6.1 
A few classes have moved packages, In this case only Element so I cleaned up the imports and one native call and it worked !
Tested on a modern system (Win7 , Chrome, FF, IE10) and the problem system (XP, IE8).
Still some IE8 specific issues such as margin and padding differences but this incredible, it actually works without vast pain.
I may have messed up the spacing ... if so I can rework that.
Merge pull request #2 from DALDEI/master

Updated code to work with GWT 2.6.1