STEMCELL_NAME is never configured
Avoid duplicate stemcell_name due to mixing string and symbol keys
Avoid default env vars that are always set
Add spec for passing an IO body to upload adapter.
Moved Bosh::Dev::Bat::BoshCliSession to Bosh::Dev::BoshCliSession
Create 'latest' file in root of artifacts bucket

This can be used for automated, continuous delivery deploys for fetching
the latest gems, release, and stemcell from our artifacts bucket without
querying and parsing the S3 bucket response.
began cleanup of the deployer instance manager spec
use open3 for running commands in deployer
Test cleanup to remove some partial stubbing
Move LoggerRender to own file, add tests, move #step
Always uses CANDIDATE_BUILD_NUMBER since it is now the build flow number
Revert "Move LoggerRender to own file, add tests, move #step"

This reverts commit b76170c5ced5fd8de99b30e36e8fd309a1306378.
Converted stemcell builder to always build micro

Stemcell builder uses options to build stemcells
whether basic or micro stemcell method is called.
The only difference is the 'stemcell_name' option,
which has remained as 'bosh-stemcell' for basic
Converted download_release to use DownloadAdapter, http download rather than s3cmd
Added tarball path to basic stemcell creation
"bosh ssh" prompts for which instance to ssh

Usage:

    $ bosh ssh
    1. service_gateways/0
    2. postgresql_service_node/0
    3. redis_service_node/0
    Choose an instance: 2
    Enter password (use it to sudo on remote host): *
    Target deployment is `cf-services-dfw2-prod-alt'

    Setting up ssh artifacts

    Director task 7791

    Task 7791 done
    Starting interactive shell on job postgresql_service_node/0
Update for style and clarity of 'pr/390'
Jenkins JOB_NAME is no longer used by bosh-dev
Revert "Create 'latest' file in root of artifacts"

This reverts commit 2242334aae2aa7b5d34f62b0cad973de5ada409b.
Build uses UploadAdapter to upload gems