Added gem nokogiri-styles.
Added the Html::Color class.
Updated the Html::Element class.

Extracted the logic about color of the element into the Html::Color class.
Added the Html::Element class.

Changed the logic of the font-size to use the nokogiri-styles gem.
Added the Html::Attributes class.

Changed the logic of the attributes to match the nokogiri-styles gem.
Updated the Html::Element class.

Removed the style of the html attributes.
Updated the Bbcode::Element class.

Updated the logic to use the nokogiri-styles gem.
Updated the Bbcode::Rules & Html::Element classes.

Use the default styles method instead of the get_styles.
By default the styles method returns an empty string, there's no need for a special null-object.
Updated the Bbcode::Rules & Html::Element classes.

The style is just color - font-color doesn't exist.
Updated the Html::Element classes.

Added supporting for the br html tag.