Bug 110331 add tests for import/export
I have written additional tests for import archive, export to file system and export to archive. And changed the import existing and import operation (file system) tests. This work required a change to the TarFile class in the ide plugin. Attachments to follow.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/wizards/datatransfer/TarFile.java
* 
	 * @param file
	 * @throws TarException
	 * @throws IOException
	 */
	public TarFile(File file) throws TarException, IOException {
		this.file = file;
		InputStream in = new FileInputStream(file);
		
		try {
			in = new GZIPInputStream(in);
		} catch(IOException e) {
			
			in = new FileInputStream(file);
		}
		entryEnumerationStream = new TarInputStream(in);
		curEntry = entryEnumerationStream.getNextEntry();
	}
	/**
	 * Create a new TarFile for the given path name.
	 * 
	 * @param filename
	 * @throws TarException
	 * @throws IOException
	 */
	public TarFile(String filename) throws TarException, IOException {
		this(new File(filename));
	}
	/**
	 * Returns an enumeration cataloguing the tar archive.