Travis CI: test "all" packages

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test Go 1.4 and 1.1
Merge pull request #55 from libgo/travisci

Travis CI test more packages, test Go 1.4
Update travis to build against 1.3 and 1.4
Test against tip
Merge pull request #57 from goamz/travis

Update travis to build against additional versions
testing: use the official gocheck package on GitHub

https://github.com/go-check/check
use dot import for gocheck

to match the official repo

https://github.com/go-amz/amz/issues/5