* gnu/javax/swing/text/html/css/BorderStyle.java: New class for
	handling border styles.
	* gnu/javax/swing/text/html/css/BorderWidth.java
	(isValid): New method.
	* gnu/javax/swing/text/html/css/Length.java
	(isValid): New method.
	* javax/swing/text/html/CSS.java
	(addInternal): Added shorthand parsing for border, padding and
	margin.
	(parseBackgroundShorthand): Added API docs.
	(parsePaddingShorthand): New method. Handles padding shorthand
	values.
	(parseMarginShorthand): New method. Handles margin shorthand
	values.
	(parseBorderShorthand): New method. Handles border shorthand
	values.
	* javax/swing/text/html/StyleSheet.java
	(translateHTMLToCSS): Set specific padding attributes.
	(BoxPainter.BoxPainter): Don't handle PADDING and MARGIN here.
	These shorthands are now handled in CSS.
	(BoxPainter.paint): Exclude the outer margin.

	* gnu/javax/swing/text/html/css/BorderWidth.java:
	New class. Handles CSS border width values.
	* gnu/javax/swing/text/html/css/Length.java
	(floatValue): Made protected so that BorderWidth can access it.
	* javax/swing/text/html/CSS.java
	(Attribute.BORDER_BOTTOM_COLOR): New static field.
	(Attribute.BORDER_BOTTOM_STYLE): New static field.
	(Attribute.BORDER_LEFT_COLOR): New static field.
	(Attribute.BORDER_LEFT_STYLE): New static field.
	(Attribute.BORDER_RIGHT_COLOR): New static field.
	(Attribute.BORDER_RIGHT_STYLE): New static field.
	(Attribute.BORDER_TOP_COLOR): New static field.
	(Attribute.BORDER_TOP_STYLE): New static field.
	(getValue): Added some mappings for the border color and
	border width values.
	* javax/swing/text/html/CSSBorder.java: New class. Implements
	CSS borders.
	* javax/swing/text/html/StyleSheet.java
	(BoxPainter.background): New field.
	(BoxPainter.border): New field.
	(BoxPainter.bottomInset): Documented.
	(BoxPainter.leftInset): Documented.
	(BoxPainter.rightInset): Documented.
	(BoxPainter.topInset): Documented.
	(BoxPainter.BoxPainter): Added support for borders and background.
	(BoxPainter.getInset): Add border insets.
	(BoxPainter.paint): Implemented. Paints the background and the
	CSS border.
	(addRule): Be less picky about parse and IO exceptions.
	(getBoxPainter): Adjust to new BoxPainter constructor.