Modified the default root project, lift-framework, to exclude json_scalaz by default.
Added a new project, `lift-framework-with-scalaz6` which adds json_scalaz and can be used
when you need lift json scalaz that uses scalaz 6

To use it you need to:

1. ++2.10.4
2. project lift-framework-with-scalaz6
3. compile //or any task you need, test, publish-local, etc

This means that from now one, if you work as you used to, you will not be comppiling lift-json-scalaz based on scalaz 6, but instead
you will be using lift-json-scalz7 based on scalaz7