Allow to update inventory's title when opened

[MinusKube]

It would be nice to be able to update the inventory's title after it has been opened, so we could make animated titles for example.

[staticvoidzach]

I really want this feature. When might it be implemented?

[GitGraf]

The only way to update the title of an inventory is to open a new inventory, but that causes all sorts of troubles with close listeners and resets the mouse to center. That's why I decided to use NMS to "fake open" a new inventory for the player.

Working with NMS is always a bit difficult, but it seems to be working reasonably well now. However some testing still needs to be done in order to ensure that no unexpected behaviour will occur when using the SmartInventory#sendTitleUpdate method.