Acli

- Add basic support for EFS
- Minor fixes

- Correct ec2 instance counts
- Fix python 3 compatibility
- Fix output issues with s3 and ec2
- Upgrade dependencies

- Improve permission checks to prevent false negatives
- Minor fixes

- Make it work with Python 2.6
- Properly report a lack of (matching) AMIs
- Let 'ls' option work for ami listing
- Fail nicely if S3 directory transfer attempted (not able to sync dirs yet)
- Check instance has tags before trying to filter on them

- Show instance counts in output for 'acli ec2 summary'

- Add filtering/searching on AMI lists

`example: acli ami ls --filter=webserver`

- Added ability to delete keys from S3

`example: acli s3 rm mybucket/myfolder/mykey.txt`

- Added filtering/searching on ec2 instance lists

`example: acli ec2 ls --filter=nginx`

- Added functions for cleaning up orphaned snapshots and unnamed and unattached volumes. (first run with --noop to check what will be removed.)

`example: acli clean delete_orphaned_snapshots --noop`

- Added bash completion script to allow tab completion of commands
- Other minor fixes