Add intPow to Number intefrace and NaiveNumber.

src/org/nwapw/abacus/number/NaiveNumber.java

@@ -41,6 +41,15 @@ public class NaiveNumber implements Number {
         return new NaiveNumber(-value);
     }
 
+    @Override
+    public Number intPow(int exponent) {
+        Number power = this;
+        for(int currentExponent = 1; currentExponent <= exponent; currentExponent++){
+            power = power.multiply(this);
+        }
+        return power;
+    }
+
     @Override
     public int compareTo(Number number) {
         NaiveNumber num = (NaiveNumber) number;

src/org/nwapw/abacus/number/Number.java

@@ -8,6 +8,7 @@ public interface Number {
     Number add(Number summand);
     Number subtract(Number subtrahend);
     Number negate();
+    Number intPow(int exponent);
     int compareTo(Number number);
     int signum();