Request for comments on exports

[AMatveev]

@odersky

We don’t want to create more special cases for them.

Can export be considered as recommended way to aggregate imports?

@kai

package myprelude
export lib1._
export lib2._
export lib3._

if it is so, and there is a compilation error in:

@dwijnand

import scala.sys.process._ 
import sbt._

it is a very hard restriction.