Selecting a tool in toolbar doesn't give it the isSelected state until typing

[tobias-g]

When you select a tool (i.e. bold, italic etc.) via clicking it in the toolbar its element doesn't gain the "sel" classname until the user begins typing in the editor.

This is because "editorStateDidChange" functions don't get called unless the editors value changes when they should be called when the editors state changes regardless of value change.

My proposed fix is https://github.com/tobias-g/rich-text-editor/compare/toolbar_selection_fix

[dcporter]

Fix looks good. Please pull req!