OSX: script to set up machine defaults
Vagrant: ignore contents of vagrant.d (except Vagrantfile)

as this is where Vagrant puts loads of stuff we don't want to be
checking in
Bash: add ~/bin_local to $PATH

for machine specific stuff I don't want to check in
Bash: move all environment setting into .bashrc
Bash: always put ~/bin in the $PATH

as there'll always be one