Fix #178: Add bridges for methods inherited from traits

All test and partests on 2.11 pass, except for 
* `pos/SI-4012-a.scala`
* `pos/SI-7638.scala`
which cause bugs in the Scala compiler, as filed in [SI-7288](https://issues.scala-lang.org/browse/SI-7288)

The increase in library size is due to the bridges we now actually generate (and should have before).