[Config] Added a mixin for round border and a tiny border size.
Docblocks.
[UI] Added module file for Buttons.
[UI] Added module file for the Dimmer.
[UI] Added module file for Dropdown menus.
[UI] Added module file for Forms.
[UI] Added module file for Icons.
[UI] Added module file for Labels.
[UI] Added module file for Messages.
[UI] Added module file for Modal windows.
[UI] Added module file for Popup tooltips.
[UI] Docblocks.