Merge View from AppCivist on all amendments (i.e., Proposals with status FORK*)

[cdparra]

1. On all amendments, add an AppCivist button to the tool bar that displays the merge view.
   -- Button label = “Ver Alterações” -- Button color = orange -- The merge view already exists and is accessible via the “Aceitar Emenda” button. But authors seem to be reluctant to click it until they are ready to accept. So we need a better way to let authors know what the amendment changes. Hopefully, adding this new button which just says that it will show the changes will help. In the future, we can think about other means, such as having all amendment text in a different color to mark additions and a deletion marker to indicate deletions. But for now, a button to show changes is better than nothing. -- Let’s try putting the new button to the right of “Aceitar Emenda” in orange.

[cdparra]

To close this, let's add the following two improvements @yolile :

• [ ] Make “Ver Alterações” available on all proposals with status FORK* (only to logged in users)
• [ ] Change the text “Revisar alterações” to “Ver/Não Ver Alterações”
• [ ] Hide the instructions box for accepting a merge when viewing getting to the merge view from the view changes button.