Add :no-project-needed to task

The task can run outside of a project.
Update to pallet-vmfest-alpha.2

Fixes an issue with supplied vbox.home property
Fix set-version regex for source file
Updated project.clj, release notes and readme for 0.6.0-beta.3
Merge branch 'release/0.6.0-beta.3'
Merge tag '0.6.0-beta.3' into develop

pallet-lein-0.6.0-beta.3
Updated version for next release cycle