Buffer tab keypresses for exact tab movement

[Novaenia]

if I have high ping (common as I'm in Australia) and press tab twice, it'll only tab once. It seems like I can only tab again once the server responds, previous implementations of Inventory Tabs did not have this issue.

[sisby-folk]

it4 doesn't buffer tab presses - the whole control setup is locked until the next screen opens.

rapidly tapping tab 3 times and guaranteeing it shows up 3 tabs across sounds good though, we'll add that.