NFS: add NFS default support.

Add default NFS support. This allows faster file sharing than with the
standard VM sharing protocol. This is espacially useful when working
with projects with a large codebase (Like a full Symfony2 installation).
README: add consistent styling.
Adds warning: NFS is not supported on Windows hosts
Merge branch 'jelmersnoeck-feature-nfs-support'
Fixes typo in README: phpMyAdmin vs phpMyADmin
Updates config.yml.example with more example configurations