cache dirs not created properly

First, great project.  It got me up and running very quickly!  Along the way I ran into two small issues.  The aptcache and pipcache folders did not exist, so there were a couple dead links during the stack.sh run.  I resolved this by issuing the following commands and rerunning stack.sh:

mkdir /home/vagrant/cache/aptcache
mkdir /home/vagrant/cache/pipcache

Cheers,
John
