Add deep copy method generation

[SoftStoneDevelop]

Now you can create a copy like this:

var tempWrap = new Benchmark.Struct.JobStructWrapper();
tempWrap.Fill(in item);
var copyItem = tempWrap.GetValue();

But this way is slow.

You need to generate something like the following:

public static JobStruct DeepCopy(in JobStruct item)
{
    var result = new JobStruct();
    result.Int32 = item.Int32;
    result.Int64 = item.Int64;
    result.JobStruct2.Int32 = item.Int32;
    result.JobStruct2.Int64 = item.Int64;

    return result;
}

Usage:

var copyItem  = JobStructHelper.DeepCopy(in item);