[platform-text-dev] headless annotation model support

[Kai-Uwe Maetzel <kai-uwe_maetzel@xxxxxxxxxx>]

We added headless annotation model support
to text file buffers. Each text file buffer
can now have its own annotation model.
        ITextFileBuffer
buffer= FileBuffers.getTextFileBufferManager().getTextFileBuffer(<location>);
        IAnnotationModel
model= buffer.getAnnotationModel();
When the buffer's document is changed,
all annotations in the buffer's annotation
model are accordingly updated.

As annotations (org.eclipse.jface.text.source.Annotation)
had dependencies on
SWT the following changes have been
applied. These changes might break existing 3.0 clients.
The changes in detail:
- ImageUtilities has been moved from
org.eclipse.ui.texteditors to org.eclipse.jface.text.source
- removed static Annotation.drawImage
methods -> use org.eclipse.jface.text.source.ImageUtilities
- removed setLayer, getLayer, and paint
from Annotation -> annotations which want to draw 
  themselves should implement IAnnotationPresentation
(as has been introduced by Dec. 18th)
- MarkerAnnotation now directly implements
the methods removed from Annotation (setLayer, getLayer, paint)
- MarkerAnnotation extends SimpleMarkerAnnotation,
SimpleMarkerAnnotation just provides
  access to the represented IMarker
- the following classes have been moved
from the plug-in org.eclipse.jface.text to the plug-in 
  org.eclipse.text, the package
names remain the same
        org.eclipse.jface.text.ISynchronizable
        org.eclipse.jface.text.source.Annotation
        org.eclipse.jface.text.source.AnnotationMap
        org.eclipse.jface.text.source.AnnotationModel
        org.eclipse.jface.text.source.AnnotationModelEvent
        org.eclipse.jface.text.source.IAnnotationMap
        org.eclipse.jface.text.source.IAnnotationModel
        org.eclipse.jface.text.source.IAnnotationModelExtension
        org.eclipse.jface.text.source.IAnnotationModelListener
        org.eclipse.jface.text.source.IAnnotationModelListenerExtension

The following changes were made to add
headless annotation model support to filebuffers.
        -
added ITextFileBuffer.getAnnotationModel(IPath)
        -
added ITextFileBufferManager.createAnnotationModel(IPath)
        -
introduced IPersistableAnnotationModel give annotations model a sense of
a life cycle
        -
added new extension point org.eclipse.core.filebuffers.annotationModelCreation
for 
         
registering factories for file buffer annotation models
        -
introduced IAnnotationModelFactory to reify the contract for the extension
point
        -
changed TextFileDocumentProvider to take the text file buffer annotation
models into
         
account. This is only the case when a subclass does override 
           
  TextFileDocumentProvider.createAnnotationModel

Theses changes are available in HEAD
and affect the following plug-ins:
        org.eclipse.core.filebuffers
        org.eclipse.jface.text
        org.eclipse.text
        org.eclipse.ui.editors

Kai