V3.0 dev

[LiFaytheGoblin]

This introduces a new version 3.0.0. (not backwards compatible).

• The error registered for a version can get very long - therefore the database column is updated to be a text. Upgrade.php handles the database change.
• fixes #17
  • Adds a ability to chose between creating a new model version automatically and manually.
  • Enables the choice of contexts for data gathering when creating a new model version manually.
  • Enables the upload of datasets instead of data gathering when creating a new model version manually.
• Refactors templates to be more modular.
• Further refactors the code.
• Updates tests.
• Fixes code style and documentation.