Bug 73082 [Encoding] Need an encoding extension point
We need to have an extension point for encodings. All it need have is the IDs of the encodings that are to be added to the list. It will require verification and indication of unavailable encodings.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/IDEEncoding.java
* Set the resource encoding to be value. Add the encoding to the list of
	 * encodings stored by the workbench.
	 * 
	 * @param value
	 *            String or <code>null</code> if the preference is to be reset
	 *            to the default.
	 */
	public static void setResourceEncoding(String value) {
		
		Preferences resourcePrefs = ResourcesPlugin.getPlugin()
				.getPluginPreferences();
		if (value == null)
			resourcePrefs.setToDefault(ResourcesPlugin.PREF_ENCODING);
		else {
			resourcePrefs.setValue(ResourcesPlugin.PREF_ENCODING, value);
			addIDEEncoding(value);
		}
		ResourcesPlugin.getPlugin().savePluginPreferences();
	}
	/**
	 * Add value to the list of workbench encodings.
	 * 
	 * @param value
	 */
	public static void addIDEEncoding(String value) {
		
		if(WorkbenchEncoding.getStandardEncodings().contains(value))
			return;
		
		String[] currentEncodings = getIDEEncodingsPreference();