Update for Lift 2.5.1, scala 2.10.2, sbt 0.12.4 + readme fixes + various minor improvements

please see commit messages / diffs for the various improvements.

Highlights:
- sbt updated to 0.12.4
- default scala version to 2.10.2
- lift updated to 2.5.1
- all dependencies and plugins updated
- all deprecations & warnings fixed
- instructions for IDEA and ENSIME added
- scalaOptions and jetty port explicitly listed for easy customisation

I trust these are generally useful improvements.