Simplified and improved its behaviour:
- return null for an empty string
- allow for an arbitrary sequence of white spaces between the scales
- check that number of arguments is no more than 2
- other small improvements


git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@803440 13f79535-47bb-0310-9956-ffa450edef68

Fixed typos.
Bugfix: when crop-offset wasn't specified, but bleed was, the media box was wrong.
Tried to fix encapsulation problem mentioned by Vincent.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@800401 13f79535-47bb-0310-9956-ffa450edef68

Added an initial set of extensions for prepress support (fox:bleed, fox:crop-offset, fox:crop-box and fox:scale). This is currently supported only by PDF and Java2D renderers.
Submitted by: Peter Coppens <pc.subscriptions.at.gmail.com>

Changes to patch by jeremias:
- crop box expands from trim box rather than the bleed box.
- fixed positioning in AWT preview

Additional changes included:
- disabled the border around every page in Java2DRenderer.
- if background painting is enabled for the Java2DRenderer, it uses the bleed box rather than the trim box.


git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@800142 13f79535-47bb-0310-9956-ffa450edef68