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
/**
	 * Answers whether a manifest must be included in the JAR.
	 * 
	 * @return <code>true</code> if a manifest has to be included
	 */
	public boolean usesManifest() {
		return fUsesManifest;
	}
	
	/**
	 * Set whether a manifest must be included in the JAR.
	 * 
	 * @param state the new state
	 */
	public void setUsesManifest(boolean state) {
		fUsesManifest= state;
	}
	
	/**
	 * Gets the manifest provider for this JAR package.
	 * 
	 * @return the IManifestProvider
	 */
	public IManifestProvider getManifestProvider() {
		if (fManifestProvider == null)
			fManifestProvider= new ManifestProvider();
		return fManifestProvider;
	}
	
	/**