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/ui/jarpackager/JarPackageData.java
* Set the manifest provider.
	 * 
	 * @param manifestProvider the ManifestProvider to set
	 */
	public void setManifestProvider(IManifestProvider manifestProvider) {
		fManifestProvider= manifestProvider;
	}
	
	/**
	 * Answers whether the JAR itself is sealed.
	 * The manifest will contain a "Sealed: true" statement.
	 * <p>
	 * This option should only be considered when the
	 * manifest file is generated.
	 * </p>
	 * 
	 * @return <code>true</code> if the JAR must be selead
	 * @see #isManifestGenerated()
	 */
	public boolean isJarSealed() {
		return fSealJar;
	}
	/**
	 * Set whether the JAR itself is sealed.
	 * The manifest will contain the following entry:
	 * Sealed: true
	 * <p>
	 * This option should only be considered when the
	 * manifest file is generated.
	 * </p>