Installing libxml2 and libxslt dependencies for Berksehlf and pinning
version to 1.4.3.
Merge pull request #7 from hectcastro/hc-berkshelf-install

Installing libxml2 and libxslt dependencies for Berksehlf and pinning version to 1.4.3.
Remove internal Berkshelf workflow.
Remove sudo cookbook dependency.
Swap in provisionerless Vagrant boxes.
Handle Chef and cookbook installations via Vagrant plugins.
Bump Riak cookbook to v2.1.0.
Make port forwarding section more concise.