Added new Sample table and Data table relationships
Corrected Sample column names
Added support in CLI
Added test for Sample table
Added data to sample.json
Corrected bug in sql.py
Added test for create_at date of sample
Renamed test-class
Cleaned up CLI
Added info about SQL structure to docs
Updated dependencies, fixes #24
Added MANIFEST.in to include test data
Merge branch 'feature/meta-table' into develop