Get rid of custom Tuple class

[Miepee]

There currently is a class called Pair which is just a custom tuple class.
I did some benchmarking (decompile every code entry in AM2R), and found out that there is no speed difference nor memory usage between using Pair, ValueTuple or Tuple.
Tuple:

ValueTuple:

Pair:

For the sake of simplicity, I chose to replace it with a ValueTuple instead.