[HEADSUP] Merging back the xml-tools branch

[Gabor Kovesdan]

Hi,

I'll be merging back the XML toolchain changes to head tomorrow around 
6pm GTM. I'll temporarily lock head to avoid conflicting changes at the 
same time and head will be reopen very soon after the merge is complete. 
At the same time, the textproc/docproj port will be updated accordingly. 
The dependencies will change in the following way:
- textproc/opensp
- www/tidy-lib
- textproc/html
- textproc/linuxdoc
- textproc/docbook-xml
+ textproc/docbook-xml-450
+ textproc/iso-schematron-xslt

The branch contains the following changes:
- Upgrade to DocBook 4.5
- Use XSLT instead of DSSSL to render XHTML-based output
- Generate PDF from PS and simplify image processing
- Fix make lint and validate the whole documentation set
- Fix rendering of TOC elements
- Fix misused link elements that resulted in a corrupt rendering
- Use more human-friendly publication data and release info rendering
- Add support for XInclude in DocBook documents
- Add support for profiling with attributes [1]
- Add support for Schematron constraints
- Add experimental epub support
- Add experimental support for XSL-FO-based printed output
- Clean up obsolete SGML constructs
- Clean up catalogs
- Drop HTML Tidy since it is not needed any more

[1] http://www.sagehill.net/docbookxsl/Profiling.html

Gabor