DB changes done, the hell starts...
Modifying populate_test_db.sql to reflect changes on the database
Fixing test_setup.py
Modifying RawData object to reflect that a single raw data can have multiple data types
Linking the preprocessed data with the prep template, rather than with the raw_data
Hating dbschema x 2
Fixing populate_test_db.sql and test_setup.py to reflect last changes on db schema
Fixing RawData object
Fixing test code for data objects
Fixing the metadata template code and tests to reflect the changes done on the database schema and the preptemplate role
Fixing commands to reflect changes on data objects
Fixing study object
Fixing processing pipeline
Modifking initialize.sql to rmeove spectra, add sff and change Fasta to Fasta-Sanger
Fixes #326
Fixing small issues due to changes on populate.sql
Adressing dicts -> sets; forgot to mention that this PR fixes #483
Adding an if exists to the delete functions
Fixing bug on metadata_template.py
Fixing some PEP8 errors