Clarifies where to find the releases

Resolves issue #644
Update gitconfig
Added get_python3_version function
Check setuptools version; also updated to 5.5.1
Merge pull request #645 from spuder/patch-1

Clarifies where to find the releases
Add Ruby 2.1.2 to the README
Merge pull request #656 from adamnbowen/patch-2

Add Ruby 2.1.2 to the README
Merge branch 'master' of https://github.com/boxen/our-boxen
Added pypy
Updated puppet modules
Updated go==1.3.1 and packer==0.6.1
Added package control module to sublime text
Updated coffee-script==1.8.0 handlebars==2.0.0 gulp=3.8.8
Updated vagrant module to 3.2.0