Add and remove a post at the bottom of the thread by clicking a button

[simonetthomas]

Click a + button at the bottom of the thread to add a new post (without cutting everything again)

• Add the button
• JS function to add the new post
• Make sure the new post is taken into account when sending the thread
• Add a button to remove a post

[simonetthomas]

Idea : to call the function to update the characters count, maybe search for the nb_char element starting from the textarea element, instead of passing the post number in argument
Edit : done