Added support for MFA in AssumeRole.
initial interface for a request hook, sample interface and example for logging
added filename to constructor
Allows use of throughput kwargs with GlobalIncludeIndex - fixes #2055.
DDB queries with GSI now work with a single filter.
Don't pull the security token from the environment or config
when a caller supplies the access key and secret
Merge pull request #2123 from jimbrowne/security-token-env-ignore

Don't pull the security token from the environment or config when a caller supplies the access key and secret. Fixes #2123.
Fixed typo.
Merge pull request #2125 from dkavanagh/request-hooks

Add request hooks and request logger. Fixes #2125.
Add failing vpc elastic ip test
Merge branch 'ddb-gsi-fix' into develop

Fixes #2122.
Route53 Record.set_alias was broken by the addition of target
health evaluation.  Fix this and add tests for the new usage
and original usage.  Include health evaluation status in to_print.
Fix route53 alias to_print and change default health eval to False
adding a tutorial for the request_hooks addition
formatting changes
Add allocation id check & reassociation kwarg to address associate method
Prefer allocation id and association id over public ip
Add unit tests to cover new connection arguments and allocation id preference
Update integration tests to properly tear down VPC
Merge branch 'sts-assume-role-additions' into develop