Try for selecting order-by columns dynamically.

Hi.
This feature is to select order-by columns dynamically.
Of course, It is possible to do same thing with only like below.
```
qA.sortBy(t=>new scala.slick.lifted.Ordered(List(t.col1.asc, t.col2.desc, ...).map(x=>(x.column.toNode, x.ord))))
```
But, I think that if there is some macro-like method, it would be better.
Use this feature like below.
```
qA.sortByUsingList(t=>List(t.col1.asc, t.col2.desc, ...))
```
If you don't like the method's name, suggest one thing please.

Thanks.