Use concrete for uniform Makefile goodness
Add support for bracketed ipv6 address literals when generating URLs

The format_s3_uri helper function calls http_uri:parse/2 and we now
specify option {ipv6_host_with_brackets, true}. This gives us basic
support for ipv6 address literals.

Note that format_s3_uri supports both virtual host and path based
bucket syntax. For IP addresses, the virtual host option returns a
value, but one that won't work. If you're using IP addresses, you need
to stick to type 'path'.
Merge pull request #10 from opscode/sf/ipv6

Add support for bracketed ipv6 address literals when generating URLs
remove warnings_as_errors flag as it stops builds on R16B03
Merge branch 'jc/warnings-not-errors'
Prevent sending duplicate content-type headers

If the user specifies a content-type header that the file should be
served with from S3 a duplicate header containing the default value will
also be set by ibrowse, resulting in a signature failure and the S3
request being refused.
use non-deprecated crypto functions