Update slider to use appearance
Move mgwt to GWT 2.6

Updated mgwt dependency to GWT 2.6-RC3.
Fixed tests and introduced Mockito for mocks
Merge branch 'master' of github.com:dankurka/mgwt
Removed use of deprecated Element class
Merge branch 'master' of https://code.google.com/p/mgwt

Conflicts:
	src/main/java/com/googlecode/mgwt/ui/UI.gwt.xml
	src/main/java/com/googlecode/mgwt/ui/client/util/CssUtil.java
	src/main/java/com/googlecode/mgwt/ui/client/util/impl/CssUtilIE9Impl.java
	src/main/java/com/googlecode/mgwt/ui/client/util/impl/CssUtilImpl.java
	src/main/java/com/googlecode/mgwt/ui/client/util/impl/FailingImpl.java
	src/main/java/com/googlecode/mgwt/ui/client/util/impl/WebkitCssUtilImpl.java
	src/main/java/com/googlecode/mgwt/ui/client/widget/slider/Slider.java