Removed section about importing ``org.scala-ide.sbt.full.library`` project

There is really no need to import the ``org.scala-ide.sbt.full.library``
project in the workspace, hence I removed the section.
Added missing ``eclipse-juno`` profile in explanation of build.sh
Added new maven profile ``sbt-new``, which is needed because of
scala-ide/scala-ide@633e0fe41868b7a47842f5f9feaa815812840375
Merge pull request #75 from scala-ide/transient/update-doc-with-new-sbt-profile

Transient/update doc with new sbt profile