change Selector#value() to respect Selector#offset()

[k-kagurazaka]

Currently, Selector#value() and Selector#valueOrNull() returns the first model whether or not to specify Selector#offset().

orma.selectFromTodo()
    .offset(10)
    .value(); // returns the 1st todo without any warning!

Of course we can do the aimed thing as

orma.selectFromTodo().get(10);

but current behavior makes me a little confusable.

So I changed these methods to respects offset.
How do you think?

[gfx]

I think it is getOrNull() that should respect offset.

BTW I preffer Math.max(offset, 0) because it is simpler than if statements.

[k-kagurazaka]

I pushed a commit based on your advice.

These commits look little messy.
I can squash & push if you like.

[gfx]

I think offset(i).get(0) and offset(i).getOrNull(0) also respect offset.

That is, value() should alyways the same as get(0).

Use offset in get() and getOrNull() instead of value().

[k-kagurazaka]

You mean offset(5).get(2) return 8th element, right?

[gfx]

Yep. It seems more natural, isn't it?

[k-kagurazaka]

All done!
Finally, code changes are quite simple, so I squashed these commits 😃

[gfx]

LGTM. Thanks for your contribution 👏