Support rerunning the installation script by restarting postgresql.

If postgresql was installed and started in a previous run, start causes:
Error: Service `postgresql` already started, use `brew services restart postgresql`

When developing changes to these scripts, it's important to be able to run and rerun this script without removing applications.
Merge pull request #235 from ManageIQ/support_reruns_where_pg_is_started

Support rerunning the installation script by restarting postgresql.
rspec and rake environment bootstrap
harness to run vagrant commands via cocaine
Port existing tests to rspec methods
Extract LaptopHelper module for test
Publish local boxes to s3 when their size is different
Halt vagrant box after tests
Reorganize files to be more ruby- and rspec- native
Symlink the vagrantfile earlier
Doc updates
stylistic improvements