JCLOUDS-123: Using Clojure core incubator-specific nilsafe in AMI service binding

Submitted by Trevor Wennblom
JCLOUDS-124: Missing ^:dynamic in Clojure blobstore example

Submitted by Trevor Wennblom
Add license headers to src/test/resources where possible, more fine-grained RAT exclusions
Adding DEPENDENCIES to rat exclude
Cleaning up lurking copyright issues/NOTICE txt
Fixes testCreateAndRunAService by fixing the outdated jetty URL
JCLOUDS-127: Added a method to check if the context is open

- Added isOpen in Context interface
- Refactoring Closer class:
  - method close can only call once
  - method close is threadsafe
  - added method getState
JCLOUDS-100. Add AWSServerErrorRetryHandler, with an increased back
off time.
Merge branch 'master' of github.com:jclouds/jclouds