Add show, hide and toggle to NavbarCollapse
Remove redundant code and use only one JSNI method
Merge pull request #97 from ArloL/navbar-collapse-fix

Add show, hide and toggle to NavbarCollapse
Remove the default GWT styles from the libraries DataGrid/CellTable. (Fixes Issue #76)
Merge remote-tracking branch 'origin/master'
Adding the HasPull interface to the NavbarCollapseButton to allow to move it to the left side of the Navbar (Fixes Issue #89)