Merge pull request #372 from reinert/master

NumberedPager implementation
Add the click() method to Button, which is present in GWT's Button
Merge pull request #376 from tamalet/addButtonClick

Add the click() method to Button, which is present in GWT's Button
Add setHover(boolean) to CellTable to be able to add the table-hover style class
Fix exception thrown during the initialization of Pagination
Merge pull request #378 from tamalet/fixPagination

Fix exception thrown during the initialization of Pagination
Merge pull request #377 from tamalet/cellTableHover

Add setHover(boolean) to CellTable to be able to add the table-hover sty...
Merge remote-tracking branch 'upstream/master'