Merge pull request #72 from ambiata/cofarrell/minor-cleanup

Minor cleanup for various unrelated things
#44: Add thrift definition for Dictionary
#44: Remove name from Dictionary
#44: Add DirIO for testing with temporary directory
#44: Alter FactsetS3ImporterSpec to use raw dictionary for ease of testing
#44: Remove unused DictionaryTextStorerS3
#44: Introduce ResultTUtil.retry
#44: Add IdentifierStorage for common Identifier file operations
#44: Update Metadata to use IdentifierStorage
#44: Add DictionaryThriftStorage for using Identifier to add dictionaries
#44: Add cat-dictionary command
#44: Always use the latest dictionary from the repository