[wpimath] Move Java classes to edu.wpi.first.math (#3316)

wpimath/src/main/java/edu/wpi/first/math/Pair.java

@@ -0,0 +1,28 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package edu.wpi.first.math;
+
+public class Pair<A, B> {
+  private final A m_first;
+  private final B m_second;
+
+  public Pair(A first, B second) {
+    m_first = first;
+    m_second = second;
+  }
+
+  public A getFirst() {
+    return m_first;
+  }
+
+  public B getSecond() {
+    return m_second;
+  }
+
+  @SuppressWarnings("ParameterName")
+  public static <A, B> Pair<A, B> of(A a, B b) {
+    return new Pair<>(a, b);
+  }
+}