it's now possible to specify an AWS credential file instead of access/secret keys
Address code review comments

Error handling logic is easier on the eyes
Added file format reminder in comments
add documentation
Merge pull request #153 from opscode/adamed-knife-294

KNIFE-294: Use credential file to specify access/secret keys
Update README.md

Fixed alignment issue in documentation.
Set default value for distro option
Incorporated review comments to add rspec test for linux distro and remove duplicate bootstrap config options
Merge pull request #155 from opscode/adamed-oc-10072

OC-10072: knife-ec2@master: "Can not find bootstrap definition for "
[KNIFE_EC2-62] Add support for IAM instance profiles.

'server create' gains an option, --iam-profile-name

'server list' output contains an extra column to show the profile name
(if one has been assigned).

'server delete' shows the profile name assigned to the instance being
deleted.
[KNIFE-154] Rename --iam-profile-name to --iam-profile.
[KNIFE-154] Remove unnecessary details from stubbed EC2 instance IAM attribute.
[KNIFE-154] Don't print IAM profile unless specified.

This applies to create/delete - list retains a column for IAM profile.
[KNIFE-154] Don't stub IAM attributes for every test.
[KNIFE-154] fix delete tests by stubbing IAM attribute
[KNIFE-154] FIX IAM attribute name for Fog.

This was inadvertently changed when the name of the (user-facing)
option was renamed.
[KNIFE-154] Bump Fog to version required for IAM profiles.
Merge pull request #157 from opscode/adamed-knife-154

KNIFE-154:  Add support for IAM instance profiles
add bootstrap proxy option
Merge pull request #159 from opscode/adamed-knife-387

KNIFE-387: knife ec2 server create should accept bootstrap proxy option
Cut version 0.6.6.rc.0

Get a testing release out there for folks