Upgrade sbt web plugin to 0.7.0

There is a 0.9.0 stable version, but I am only bumping it up to 0.9.0 given that that is what we find in
https://github.com/lift/lift_26_sbt/blob/master/scala_211/lift_{blank, basic, json, mvc}/project/plugins.sbt
Upgrade to Scala 2.11.1 & Lift 2.6-RC1

Making this build.sbt be in sync with https://github.com/lift/lift_26_sbt/blob/master/scala_211/lift_{blank, basic, json, mvc}/build.sbt
Merge pull request #5 from jcaraballo/dependencies-upgrade

Dependencies upgrade