Add Vagrantfile to enable emulating Travis-CI env.

 - Use Vagrant to emulate the Travis-CI Precise environment

```
echo "install vagrant, # Do this first. On OS X w/ homebrew:"
brew cask install vagrant # only if you have homebrew/OSX
cd developer-scripts
vagrant init
vagrant up
vagrant ssh # now you're in!
```
[CI skip]

Author: zbeekman

developer-scripts/Vagrantfile

@@ -0,0 +1,98 @@
+# -*- mode: ruby -*-
+# vi: set ft=ruby :
+VAGRANT_COMMAND = ARGV[0]
+
+# All Vagrant configuration is done below. The "2" in Vagrant.configure
+# configures the configuration version (we support older styles for
+# backwards compatibility). Please don't change it unless you know what
+# you're doing.
+Vagrant.configure(2) do |config|
+  # The most common configuration options are documented and commented below.
+  # For a complete reference, please see the online documentation at
+  # https://docs.vagrantup.com.
+
+  # Every Vagrant development environment requires a box. You can search for
+  # boxes at https://atlas.hashicorp.com/search.
+  config.vm.box = "hashicorp/precise64"
+
+  # Disable automatic box update checking. If you disable this, then
+  # boxes will only be checked for updates when the user runs
+  # `vagrant box outdated`. This is not recommended.
+  config.vm.box_check_update = true
+
+  # Create a forwarded port mapping which allows access to a specific port
+  # within the machine from a port on the host machine. In the example below,
+  # accessing "localhost:8080" will access port 80 on the guest machine.
+  # config.vm.network "forwarded_port", guest: 80, host: 8080
+
+  # Create a private network, which allows host-only access to the machine
+  # using a specific IP.
+  # config.vm.network "private_network", ip: "192.168.33.10"
+
+  # Create a public network, which generally matched to bridged network.
+  # Bridged networks make the machine appear as another physical device on
+  # your network.
+  # config.vm.network "public_network"
+
+  # Share an additional folder to the guest VM. The first argument is
+  # the path on the host to the actual folder. The second argument is
+  # the path on the guest to mount the folder. And the optional third
+  # argument is a set of non-required options.
+  config.vm.synced_folder "..", "/home/travis/build/sourceryinstitute/opencoarrays", mount_options: ["dmode=2770", "fmode=660"]
+
+
+  # Provider-specific configuration so you can fine-tune various
+  # backing providers for Vagrant. These expose provider-specific options.
+  # Example for VirtualBox:
+  #
+  # config.vm.provider "virtualbox" do |vb|
+  #   # Display the VirtualBox GUI when booting the machine
+  #   vb.gui = true
+  #
+  #   # Customize the amount of memory on the VM:
+  #   vb.memory = "1024"
+  # end
+  #
+  # View the documentation for the provider you are using for more
+  # information on available options.
+
+  # Define a Vagrant Push strategy for pushing to Atlas. Other push strategies
+  # such as FTP and Heroku are also available. See the documentation at
+  # https://docs.vagrantup.com/v2/push/atlas.html for more information.
+  # config.push.define "atlas" do |push|
+  #   push.app = "YOUR_ATLAS_USERNAME/YOUR_APPLICATION_NAME"
+  # end
+
+  config.ssh.insert_key = true
+  # try to set a different default user
+    if VAGRANT_COMMAND == "ssh"
+      config.ssh.username = 'travis'
+      config.ssh.insert_key = true
+    end
+
+  # config.ssh.username = "travis"
+  # config.ssh.insert_key = false
+
+  # Enable provisioning with a shell script. Additional provisioners such as
+  # Puppet, Chef, Ansible, Salt, and Docker are also available. Please see the
+  # documentation for more information about their specific syntax and use.
+  config.vm.provision "shell", inline: <<-SHELL
+    useradd -m -s /bin/bash travis
+    usermod -a -G vagrant travis
+    echo -e "travis\ntravis\n" | sudo passwd travis
+    [ -d /home/travis/.ssh ] || sudo mkdir -p /home/travis/.ssh
+    cp /home/vagrant/.ssh/authorized_keys /home/travis/.ssh/
+    sudo chown -R travis:travis /home/travis
+    sudo chmod 600 /home/travis/.ssh/authorized_keys
+    sudo chown travis:travis /home/travis/.ssh/authorized_keys
+    # sudo echo "AllowUsers travis" >> /etc/ssh/sshd_config
+    # echo 'linuxbrew ALL=(ALL) NOPASSWD:ALL' >>/etc/sudoers # emulate no sudo on travis
+    sudo apt-get update
+    sudo apt-get update --fix-missing -y
+    sudo apt-get install -y gawk build-essential ruby curl git jq python-pip python-setuptools
+    unset LD_LIBRARY_PATH PKG_CONFIG_PATH
+    echo 'sudo su -l travis' | cat >> /home/vagrant/.bash_profile
+    echo 'export PATH="${HOME}/.linuxbrew/bin:$PATH"' | cat >> /home/travis/.bash_profile
+    echo 'cd ${HOME}/build/sourceryinstitute/opencoarrays' | cat >> /home/travis/.bash_profile
+  SHELL
+end