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
"WorkbenchPreference.defaultEncoding", new String[] { defaultEnc })); 
        data = new GridData();
        data.horizontalSpan = 2;
        defaultEncodingButton.setLayoutData(data);
        defaultEncodingButton.addSelectionListener(buttonListener);
        defaultEncodingButton.setFont(font);
        otherEncodingButton = new Button(group, SWT.RADIO);
        otherEncodingButton.setText(IDEWorkbenchMessages
                .getString("WorkbenchPreference.otherEncoding")); 
        otherEncodingButton.addSelectionListener(buttonListener);
        otherEncodingButton.setFont(font);
        encodingCombo = new Combo(group, SWT.NONE);
        data = new GridData();
        data.widthHint = convertWidthInCharsToPixels(15);
        encodingCombo.setFont(font);
        encodingCombo.setLayoutData(data);
        encodingCombo.addModifyListener(new ModifyListener() {
            public void modifyText(ModifyEvent e) {
                updateValidState();
            }
        });
        List encodings = IDEEncoding.getIDEEncodings();
        String [] encodingStrings = new String[encodings.size()];
        encodings.toArray(encodingStrings);
        encodingCombo.setItems(encodingStrings);
        
       
        String resourcePreference = IDEEncoding.getResourceEncoding();
        boolean isDefault = resourcePreference == null;