Make ToolBarDefinitions public to allow excluding default toolbar items #363

Dear all,

First of all, thank you for your excellent work. I use Gemini as the framework for my application and really like its design.

I now want to exclude some default toolbar items using ExcludeToolBarDefinition, as I already did with ExcludeMenuDefinition, but ToolBarDefinitions is internal, so I can't access the default items.

Thank you in advance.
Tobias