remove precompiled compiler bridges
remove precompiled compiler bridges

- Scala 2.8.x or 2.9.x are no longer used that often.
- Precompiled is a cross build liability as sbt (2.10.4) depends on 2.8.x/2.9.x code.
- Scripted test was modified to check 2.8 and 2.9 compilation

xuwei-k/xsbt,xuwei-k/xsbt,mdedetrich/sbt,sbt/sbt,mdedetrich/sbt,mdedetrich/sbt,sbt/sbt,xuwei-k/xsbt,mdedetrich/sbt,mdedetrich/sbt,Duhemm/util,xuwei-k/xsbt,sbt/sbt,mdedetrich/sbt,xuwei-k/xsbt,sbt/sbt,mdedetrich/sbt,sbt/sbt,sbt/sbt,sbt/sbt