Introduce the vital / to find security-credentials

We can't get meta-data/iam/security-credentials, we need to get
meta-data/iam/security-credentials/ to actually get the roles
Update Elastic Beanstalk module to support worker environments.  Fixes #1910.
Fix unit tests to match correct meta-data security credentials URL
Merge pull request #1912 from danielgtaylor/bugfix-iam

Bug fix for IAM security credentials metadata URL. Fixes #1912, #1908, #1907.
Release notes and version bump for 2.20.1
Update RDS documentation for API version: 2013-09-09
Merge pull request #1914 from mohangk/develop

Update RDS documentation for API version: 2013-09-09
sriovNetSupport instance attribute
Merge pull request #1915 from rayrayson/develop

Documentation: sriovNetSupport instance attribute
Add AddTags support for EMR connections.

Closes issue #1909 in upstream.

See http://docs.aws.amazon.com/ElasticMapReduce/latest/API/API_AddTags.html
Typo fix.
add Kinesis to generated docs
fix length of ==== heading markers in Kinesis ref doc
Merge pull request #1921 from cce/kinesis_docs

Documentation: add Kinesis API reference
Add support for OpsWorks IAM user permissions per stack
Update integration test to check for new authorization error which is now sent before a validation error after an upstream service update.
Merge pull request #1920 from tmacam/AddEMRAddTagSupport

Add AddTags support for EMR connections. Fixes #1920.
Reworking docstrings for tier_name and tier_type to (hopefully) better explain the linkage.
Merge pull request #1911 from garnaat/beanstalk-tiers

Update Elastic Beanstalk module to support worker environments.