feat: static_proxy.

[skykaka]

Generate static proxy for mapper class for the user can use the mapper without the mapper object.

Which is discussed at #57 (comment).

[smotastic]

Hi @skykaka
Thank you for the contribution,
As discussed I like the idea, so I'll make sure to check it out on the weekend

[skykaka]

Hi @smotastic
The code is not reviewed. Have you been busy recently, or is there some problem?

[smotastic]

Hey, sorry I couldn't check the changes out last week. As you assumed I was very busy. But I like the change overall, just one small suggestion in the code.

[skykaka]

Hi @smotastic
Very import suggestion. The name "static" is so arbitrary. I haven't thought enough about this. The name  'generateStaticProxy' is good enough. It's very clear. I think we'd better use this name. I will finish the modification of the code in the next few days.