Faster delete

[M1cha]

On the web, I can quickly delete tens of messages by repeatedly hitting the delete button(which thankfully stays in the same place) very quickly. On Android you can only do like one per second because there's a delay. It may or may not just be an UI animation issue.

#301 might be a dependency of this to not fill up the screen with toast messages.

[jmattheis]

#301 shouldn't be a dependency. Only the last deleted message can be undone. If another message will be deleted while the undo toast is shown. The older message will be permanently deleted.

This should only be an enhancement for the animation speed for deletion.