Started to implement a resource tracking facility in the PSGenerator. It tracks resou...

Started to implement a resource tracking facility in the PSGenerator. It tracks resources such as EPS files, procset etc. as PSResource instances.
Resource-DSC comments are now generated.
Procsets moved into the Prolog where they belong.
Font setup is no longer a resource as it is not interchangeable between rendering runs. It's now just setup code with FOP-specific comments surrounding it.
In the future, this may also make it possible to write a size-optimized PS file from which the resources are stripped while writing the file. These resources will then be installed directly on a printer or inserted into the Prolog by a post-processor.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@239419 13f79535-47bb-0310-9956-ffa450edef68