CloudStackApi should extend Closeable

Without that, you can't actually do view.unwrapApi(CloudStackApi.class).
JCLOUDS-303. unwrap should permit subtypes
JCLOUDS-303. unhook ApiMetadata type hierarchy from ec2
[JCLOUDS-302] Remove unnecessary String construction in HttpUtils
JCLOUDS-305. Disable S3 virtual host buckets for generic S3

Not all S3-compatible providers support virtual host buckets and thus
we should disable this feature by default.  Continue to enable virtual
host buckets for AWS-S3 which supports this although this feature
suffers from DNS settling issues.  Ran ran integration tests against
AWS-S3 and Scality using its S3 API.
JCLOUDS-304. Remove broken terremark providers
Fix EC2 live tests

This removes
org.jclouds.ec2.compute.functions.PasswordCredentialsFromWindowsInstanceLiveTest
due to there not being an easily detectable valid AMI for it to run,
and low interest in actually running it in the first place.
Fix aws-ec2 live tests

Involves some non-trivial reworking of EC2 security group
translation/binding, but it was necessary.

Still problems with a number of tests:
- org.jclouds.aws.ec2.compute.AWSEC2TemplateBuilderLiveTest#testTemplateBuilderWithLessRegions
- org.jclouds.ec2.compute.EC2TemplateBuilderLiveTest#testTemplateBuilderCanUseImageIdWithoutFetchingAllImages

Those seem to be failing because there's caching going on that they're
not expecting, but I could be wrong.

Also failing:
- org.jclouds.aws.ec2.features.PlacementGroupApiLiveTest in general
- org.jclouds.aws.ec2.features.SpotInstanceApiLiveTest - a couple tests
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