Bug 37197 Basepath for relative pathes in JAR-exporter
The basepath for the JAR-exporter is the eclipse-install-directory. I prefer it to be the root of the project (the description is saved in), so that relative pathes end inside the project. Now: <jardesc> <jar path="workspace/projectdir/jar.jar"/> Desired: <jardesc> <jar path="jar.jar"/> Reason: To make the jardesc-files portable for shared projects
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/jarpackager/JarFileExportOperation.java
exportClassFiles(progressMonitor, pkgRoot, resource, jProject, destinationPath);
			exportResource(progressMonitor, pkgRoot, isInJavaProject, resource, destinationPath, isInOutputFolder);
			progressMonitor.worked(1);
			ModalContext.checkCanceled(progressMonitor);
		} else
			exportContainer(progressMonitor, (IContainer)resource);
	}
	private void exportJavaElement(IProgressMonitor progressMonitor, IJavaElement je) throws java.lang.InterruptedException {
		if (je.getElementType() == IJavaElement.PACKAGE_FRAGMENT_ROOT && ((IPackageFragmentRoot)je).isArchive())
			return;
		Object[] children= fJavaElementContentProvider.getChildren(je);
		for (int i= 0; i < children.length; i++)
			exportElement(children[i], progressMonitor);
	}
	private void exportContainer(IProgressMonitor progressMonitor, IContainer container) throws java.lang.InterruptedException {
		if (container.getType() == IResource.FOLDER && isOutputFolder((IFolder)container))
			return;
		
		IResource[] children= null;
		try {
			children= container.members();
		} catch (CoreException e) {
			
			addWarning(JarPackagerMessages.getFormattedString("JarFileExportOperation.errorDuringExport", container.getFullPath()), e); 
		}
		for (int i= 0; i < children.length; i++)
			exportElement(children[i], progressMonitor);
	}
	private IPackageFragmentRoot findPackageFragmentRoot(IJavaProject jProject, IPath path) throws JavaModelException {
		if (jProject == null || path == null || path.segmentCount() <= 0)