Add comparer for IfAttributes

[Paul-1379]

Add the ability to make comparisons directly in the ifAttribute like:

using BaseTool;
using UnityEngine;

public class MonoScript : MonoBehaviour 
{
    public int Number;
    [If("Number == 0")] public int OtherNumber;
}

or:

using BaseTool;
using UnityEngine;

public class MonoScript : MonoBehaviour 
{
    public enum MyEnum
    {
        A,
        B
    }
    public MyEnum Enum;
    [If("Enumr == MyEnum.A")] public int Number;
}

[DarkRewar]

I've searched many informations about this and... I think this would be a really long and hard task to do that. I now understand why tools like OdinInspector aren't free. I would try maybe someday something, but it is a huge task...