Remove AWSSDK as a dependency

Merge pull request #7 from invenia/ed/rm-awssdk

Remove AWSSDK dependency

Bugfixes, retries, and compat for 0.6 through 1.0

• empty tag dict bugfix
• retry every AWS operation, and MbedExceptions
• support Julia 0.6, 0.7, and 1.0

First release

Merge pull request #1 from invenia/ed/groups

Add ability to create and destroy log groups