Adds null checking invocations to Actions

ActionExtensions.cs

using System;

public static class ActionExtensions {

    public static void SafeInvoke(this Action action) {
        if (action != null) {
            action();
        }
    }

    public static void SafeInvoke<T>(this Action<T> action, T value) {
        if (action != null) {
            action(value);
        } 
    }

    public static void SafeInvoke<T, U>(this Action<T, U> action, T value0, U value1) {
        if (action != null) {
            action(value0, value1);
        }
    }

    public static void SafeInvoke<T, U, V>(this Action<T, U, V> action, T value0, U value1, V value2) {
        if (action != null) {
            action(value0, value1, value2);
        } 
    }
}