Execution

Just for feedback
Ok, this is my current plan:

```
// bring all the task functions together in one object (api.exec.Maestro instead of api.Maestro)
object Maestro = ... 

// the package object holds everything else
package object = {
  type MacroSupport = ... // no MaestroExecution trait anymore

  // if you import api.exec._, you'll get the parlour monoid instances
  // if you only import specific items from api.exec, and you want the monoid instances,
  // you'll also need to import api.exec.ParlourInstances._
  val ParlourInstances = ParlourMonoidInstances
  val myFirstParlourInstance = ParlourInstances.myFirstParlourInstance
  val mySecondParlourInstance = ...
}
```

So user code can look like:
```
import foo.bar.api.exec._

Maestro.sqoopImport(MaestroConfig(stuff).sqoopImport())
```
or
```
import foo.bar.api.exec._
import foo.bar.api.exec.Maestro._

sqoopImport(MaestroConfig(stuff).sqoopImport())
```
or
```
import foo.bar.api.exec.{Maestro, MaestroConfig}
import foo.bar.api.exec.ParlourInstances._

Maestro.sqoopImport(MaestroConfig(stuff).sqoopImport())
```