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
boolean addValue = true;
		StringBuffer result = new StringBuffer();
		for (int i = 0; i < currentEncodings.length; i++) {
			String string = currentEncodings[i];
			result.append(string);
			result.append(PREFERENCE_SEPARATOR);
			if (string.equals(value))
				addValue = false;
		}
		if (addValue)
			result.append(value);
		IDEWorkbenchPlugin.getDefault().getPreferenceStore().setValue(
				IDE_ENCODINGS_PREFERENCE, result.toString());
	}
	/**
	 * Get the value of the encodings preference.
	 * 
	 * @return List
	 */
	private static String[] getIDEEncodingsPreference() {
		String encodings = IDEWorkbenchPlugin.getDefault().getPreferenceStore()
				.getString(IDE_ENCODINGS_PREFERENCE);
		if (encodings == null || encodings.length() == 0)
			return new String[0];
		return encodings.split(PREFERENCE_SEPARATOR);
	}
	/**
	 * Clear the IDE encodings preference.
	 */
	public static void clearUserEncodings() {