Display translated titles dinamicaly for pages

I just committed a fix for displaying the translated title in view mode.

In edit mode, though, the user will see some velocity content in the title field.

The fix for displaying correctly the title in edit mode is not that simple.

1. In edit mode, one solution would be to replace the title dynamically with JavaScript, but for example, the inline editor feature generates multiple update events on the DOM and the translated title is loaded with a visible delay.

2. Another solution would be to hide the title field in edit mode if the page is detected as being translated.

3. Another solution would be to use sheets for book pages and for versioned content pages. The downside here is the fact that the UI of the page must be defined in the sheet (displaying the title, the content), rather that relying on the standard UI.