ec2: support RunInstances with BlockDeviceMappings
Set Instance.State in ec2test
Use testing.invalid rather than example.com for test DNSName values
Added IP addresses to Instance struct
merged example_dns so we have access to the changed test server names
s3: add Retry
add support for ip addresses returned from amazon
s3: implement RetryAttempts
s3: adjust comment for review
s3: expose RetryAttempts

By doing this, we allow test code external to
goamz to adjust the timeout duration. It's particularly
useful when running against s3test - by changing
this we can reduce the time it takes to test
launchpad.net/juju-core/environs/ec2 from
3 minutes to 6 seconds.

R=dimitern, jameinel, niemeyer
CC=
https://codereview.appspot.com/12740044
Clean up address code and testing
Merge trunk to resolve conflict in ec2test server
Store seq on Instance rather than id as suggested by rogpeppe in review
ec2: Add IP addresses to Instance struct

Expose IPAddress and PrivateIPAddress on Instance and add
sample values to ec2test server.

R=rog, niemeyer
CC=
https://codereview.appspot.com/12768044
Support security groups in instance responses at the instance level as well as at the reservation level
Support instance prefix on group-name and group-id instance filters
ec2: Support groups at instance and reservation

Per the 2011-12-15 wsdl description of the EC2 api, the
GroupSetType containing security group details appears
on both ReservationInfoType and RunningInstancesSetType
inside it.

This branch updates the code to parse the details at both
levels in a RunInstances or DescribeInstances response,
and updates the mock server to return the same details
at both levels.

Change is required as it seems the reservation group set
is empty, while the instance group set is not in some
circumstances.

R=rog
CC=
https://codereview.appspot.com/14302043
ec2: support instance prefix on group filters

The EC2 API documentation allows for alternative spellings of
the group-name and group-id filters on instances. It seems only
the prefixed forms are actually supported when using default VPC
despite claims to the contrary, so add support for them to the
test server infrastructure.

R=rog
CC=
https://codereview.appspot.com/14304043
Merged from trunk.
ec2: support RunInstances with BlockDeviceMappings

R=dfc, nate.finch
CC=
https://codereview.appspot.com/9860044