Remove duplicate HasEnabled definition and EnabledMixin

Bootstrap does not have .disabled styles for input elements. Therefore it is not necessary to override the existing isEnabled/setEnabled.
Make Input extend ValueBoxBase and remove redundant code
Updating the TabListItem to allow for proper setEnable(true/false), with tabs you must remove the data-toggle="tab" to properly disable it and add it back when enabling it.
Moving the method to rebuild the Pagination based on the SimplePager of the CellTable/DataGrid into the Pagination itself to make it easier for users to rebuild the pagination.
Updating the PanelHeader to extend HTMLPanel so that we can have widgets and text.
Updating the Icon to include getters for all the settings, also removing the check for NONE to allow to reset/remove the spin/size/etc.
#104 avoiding empty-classnames, using different basename than GWT instead
Merge pull request #105 from rlf/master

#104 avoiding empty-classnames, using different basename than GWT instead
#76 better conformance with Bootstrap3 styles for CellTable (stripes/hovers still wins over selection)
Bumped gwt to 2.6.0
Updating DataGrid to avoid empty style names.
Adding method to set the modal width on the modal.
Merge pull request #106 from rlf/master

More minimalistic style-naming for the CellTable
Merge pull request #101 from ArloL/input-valuebox

Cleanup ValueBoxBase and make Input extend ValueBoxBase
Updating the DataGrid css to reflect the CellTable css.
Removing the custom CSS needed for Left/Right/Bottom tabs and putting it in the Extras so that the CSS won't be injected many times. (Fixes Issue #86)
NavbarCollapse didnt pass the command to the JSNI method (Fixes issue #107)
Fix #102 by making CheckBox implement IsEditor
Merge pull request #108 from ArloL/checkbox-editor

Fix #102 by making CheckBox implement IsEditor
PanelCollapse#setIn() should remove style when value is false. Added missing getter.