Custom button arrangement

Feature Request: #463

Working Features:
<ul>
<li>Creating sections and Commands</li>
<li>Sorting By Row and Index (automatically done)</li>
<li>Layouting through Row, Index and Offset</li>
<li>At the control Tab: Sections can be Collapsed</li>
</ul>

Thinking about making Sections hideable. Interested?
Could be useful to hide Calibration commands, so that they don't use any space.