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/internal/ide/dialogs/IDEEditorsPreferencePage.java
createEditorReuseGroup(composite);
        createSpace(composite);
        createEncodingGroup(composite);
        updateValidState();
        
        
        return composite;
    }
    private void createEncodingGroup(Composite parent) {
        Font font = parent.getFont();
        Group group = new Group(parent, SWT.NONE);
        GridData data = new GridData(GridData.FILL_HORIZONTAL);
        group.setLayoutData(data);
        GridLayout layout = new GridLayout();
        layout.numColumns = 2;
        group.setLayout(layout);
        group.setText(IDEWorkbenchMessages
                .getString("WorkbenchPreference.encoding")); 
        group.setFont(font);
        SelectionAdapter buttonListener = new SelectionAdapter() {
            public void widgetSelected(SelectionEvent e) {
                updateEncodingState(defaultEncodingButton.getSelection());
                updateValidState();
            }
        };
        defaultEncodingButton = new Button(group, SWT.RADIO);
        defaultEnc =  WorkbenchEncoding.getWorkbenchDefaultEncoding();
        defaultEncodingButton
                .setText(IDEWorkbenchMessages
                        .format(