Adding an attack animation to most attacks

* Adding attack animation to most melee attacks from mob/living creatures.
* Fixing a couple typos and  "for(......) show_message()".
* Fixing the pixel offset issue from beds especially rollerbed. (probably fixes #5228 )
* Fixing the nograv bouncing permanently stopping because of another animation being used.(lying down, jittering, attack animation). (Probably fixes #3926)

The attack animation is played for pretty much any mob melee attack that shows a message. It's a quick move forward that lasts roughly half a second. The main advantages of this animation is the advanced immersion and making identifying the attackers in a crowded place much easier. This works for pretty much all mob/living that have attacks. Diagonal attacks moves the mob in the direction he's facing, because I'm too lazy to search how to make a diagonal move.

The animation doesn't play for hugging, grabbing, handcuffing, constructing machines, help intent related actions,etc.. If you see the animation then the mob is most likely trying to damage whatever it's aiming at.

Shitty gif to get an idea of how it looks: (<B> Edited into the OP - Remie</B>)

![](http://oi58.tinypic.com/303hl4l.gif)
```
if(NORTHEAST)
    pixel_x_diff = 8
    pixel_y_diff = 8
if(SOUTHEAST)
    pixel_x_diff = 8
    pixel_y_diff = -8
```
etc. for diagonal moves.
probably also best to swap the if(1) if(2) stuff with the NORTH, EAST etc. defines/consts.