Use the new Travis Docker infrastructure and stuff

Fix tutorial source ID
[skip ci]

`ami-9eaa1cf6` is the correct Ubuntu 14.04 AMI for the us-east-1 region.

Fixes #1841

Adding documentation for the environments_path
[skip ci]

Docs fixes for shell provisioner page

website/intro/getting-started: clarify that multiple builders of the same type must have a unique name

Fixes #1718 
[skip ci]

[skip ci]

SCSI Support in virtualbox driver

virtualbox.

s/VirtualBox/VMware in comment
[skip ci]

Fix documentation for openstack_provider and provider config options. 
[skip ci]

builder/parallels: Use most recent DHCP lease when determining IP.

Update plugins.html.markdown

I think this is the required PATH for windows.

Fix amazon instance type on build an image page [skip ci]

[skip ci]

Add `--retcode-passthrough` to salt-call so the build fails when there is an error running `highstate`

This page referred to using a "t1.micro" instance but the template actually uses a "t2.micro".

Create temporary copy of symlink before uploading, fixes #1765

Updated Amazon documentation to reflect use of credentials file
[skip ci]

Allow manifest_file to be a directory for Puppet Masterless Porvisioner

Fix link to shell provisioner [skip ci]

Escapes cp alias, fixes #1656

Changed type of version.number / vagrant-cloud post-processor
Fixes #1735 

Added Chocolatey as alternative installation [skip ci]