Fix --dry-run bug

Minor bugfix - see previous release for recent breaking changes:
https://github.com/AppliedTrust/amibackup/releases/tag/v0.13

Attached binaries are for 64-bit Linux.

Significant update - breaking changes

Update to official AWS SDK, address issue with tagging before image is ready, lots of refactor/cleanup.

Attached binaries are for 64-bit Linux.

Bug fixes:

• Wait until AMI is ready to CreateTags.

New features:

• Backup multiple instances in parallel by specifying more than one <instance_name_tag>

Breaking changes:

• Switch to official AWS SDK requires different authentication settings (see: https://github.com/aws/aws-sdk-go#configuring-credentials)
• --timeout flag uses Go-style time specifier (ex: 10s, 1m, 2h) instead of raw seconds.
• --nagios flag is no longer supported.
• --debug flag is no longer supported.

Bug fix: incorrect purge window calculation

Fixed bug where purge window calculation is wrong.

When: window interval > stop-start
Because: because cursor = start + interval

Linux binary

v0.10

Don't freak out on failed purges