Changed FeatureStore/Dictionary to only deal with Store abstraction

- Removed filesystem specific code from FeatureStore and Dictionary
- Removed FeatureStore importer and creation cli
- Changed interface to use ResultTIO instead of ScoobiAction or Hdfs
- Added tests for FeatureStore
- Changed most uses of HdfsRepository to Repository
- All paths changed to Reference (Store, FilePath) pair
Update docs
Tests for store path listing
fix tests
Added back FlatFactThriftStorageV1 to Chord, removed job.setOutputFormatClass from FactsetJob as its not needed
Merge pull request #121 from ambiata/topic/generalize-metadata

generalize metadata
Rename StructValue to avoid name clash with fact values
Cleanup FactDiffSpec
Simply validateEncoding for just Values
Introduce ValidateSpec
Remove unused stringValue on Fact
Remove unnecessary parens in case if
Add missing case for EavtParsers for StructEncoding
Move Value.encoding to only consumer Validate
Remove duplicate code from Fact.safeCopy
Remove unused Fact.safeCopy
Add Structs to Facts
Introduce Maps.outerJoin for convenient dictionary validation
Update DictionaryImportValidation to use Maps.outerJoin
Update Validation use Maps.outerJoin