Update to include travis docker support

From: http://blog.travis-ci.com/2014-12-17-faster-builds-with-container-based-infrastructure/
Revert travis update.

Revert as we require sudo for apt-get and I didn't read the instructions carefully.
bump middleware
uncomment accidentally commented test :-/
Merge pull request #712 from fommil/master

Housekeeping (and uncommenting some tests)
bump sbt version
use scala 2.11.4 for the master build
revert sbt version bump
Merge pull request #713 from fommil/master

revert sbt version bump
Fix missing line/offsets when looking up symbol positions

Fixes #630