aws-rb support --profile option.

--profile option read standard credential file
Merge pull request #576 from muramasa64/aws-rb-support-profile

aws-rb support --profile option.
Refs #575: Fixed issue in assigning metadata to S3 object through S3Object.write().

Signed-off-by: Gautam Sathe <gautam@hemisphereinteractive.com>
API Update for AWS Support
API Update for AWS IAM

This release adds support for AWS IAM self-service password rotation
features and retrieval of credential reports.
Doc Updates for Amazon CloudSearch
Tag release v1.48.0

References:
  #576, #577
Merge pull request #578 from matuag/bug-575

Refs #575: Fixed issue in assigning metadata to S3 object
Updated the bundled list of supported AWS endpoints.
Replaced a 1.9 hash syntax usage with 1.8.7 compat.
Resolved an issue with the AWS::S3 client-side-encryption CipherIO class.
Reverted commit e475224b5 due to a regression with S3 client-side-encryption.

See #558
Tag release v1.48.1

References:
  #558, #575, #578