Don't check velocities on Projectiles

Closes GH-217

Spigot-Server-Patches/Add-velocity-warnings.patch

@@ -13,8 +13,8 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
  
      public void setVelocity(Vector vel) {
 +        // Paper start - Warn server owners when plugins try to set super high velocities
-+        if (vel.getX() > 4 || vel.getX() < -4 || vel.getY() > 4 || vel.getY() < -4 || vel.getZ() > 4 || vel.getZ() < -4) {
-+            getServer().getLogger().warning("Excessive velocity set detected: tried to set velocity of entity #"+getEntityId()+" to ("+vel.getX()+","+vel.getY()+","+vel.getZ()+").");
++        if (!(this instanceof org.bukkit.entity.Projectile) && (vel.getX() > 4 || vel.getX() < -4 || vel.getY() > 4 || vel.getY() < -4 || vel.getZ() > 4 || vel.getZ() < -4)) {
++            getServer().getLogger().warning("Excessive velocity set detected: tried to set velocity of entity #" + getEntityId() + " to (" + vel.getX() + "," + vel.getY() + "," + vel.getZ() + ").");
 +            Thread.dumpStack();
 +        }
 +        // Paper end