Try for SQL String Indentation.

Hi.

At first, My English is not good.

This work is SQL-Indentation.
This work doesn't Commercial Quality Indentation.
However, When debug, if there are any indentation features, I think that it is better than nothing.

My original purpose was doing indentation per each session.
Let's assume that there is a the sqlIndent flag in `scala.slick.backend.SessionDef`.
I couldn't know how to pass this flag status to `scala.slick.compiler.CompilerState`.
So, In this work, this indentation flag is configured in each `JdbcStatementBuilderComponent` instances.
So, If you create a driver instance, you can't change this flag status with the instance.
If you want a different flag status, you should create new driver instance.

Usage is like below.
```
trait NewH2Driver extends H2Driver { driver =>

  override val sqlIndent: Boolean = true
...
}

object NewH2Driver extends NewH2Driver
```
By the way, this Pull Request's the sqlIndent flag's default value is true.
Because, I wanted to show that this feature doesn't make any side-effect about every calculations and results.
And, I couldn't know how to change indentation flag for only Test drivers.

Thanks.