Fixed Amazon S3 client

I've been fixing stuff – see pull requests:

Fixed the offline tests and configured Travis CI (comments)
https://github.com/zendframework/ZendService_Amazon/pull/18

-- not merged, but closed --

Fix whitespace and indentation
https://github.com/zendframework/ZendService_Amazon/pull/24

Update http client usage
https://github.com/zendframework/ZendService_Amazon/pull/26

Fix etag header
https://github.com/zendframework/ZendService_Amazon/pull/27

Travis config
https://github.com/zendframework/ZendService_Amazon/pull/32

-- merged on 19.11.2012 --

Fix exceptions
https://github.com/zendframework/ZendService_Amazon/pull/25

Fix test common prefixes
https://github.com/zendframework/ZendService_Amazon/pull/28

Fix region logic
https://github.com/zendframework/ZendService_Amazon/pull/29

Fix phpunit 37x
https://github.com/zendframework/ZendService_Amazon/pull/30

Fix bad bucket name tests
https://github.com/zendframework/ZendService_Amazon/pull/31

Throttle requests
https://github.com/zendframework/ZendService_Amazon/pull/33

Psr2 fixes
https://github.com/zendframework/ZendService_Amazon/pull/34

And:

Fix error checking on Zend\Http\Client\Adapter\Socket->write() 
https://github.com/zendframework/zf2/pull/3033