Just a small PHP Docblock addition
- Refactoring of certificates table, add possibility to display certificates from a given user
Factor out some logic from form GUI classes to the settings models (still it would be better to factor out each setting into its own class)
Refactor Settings in order to introduce custom settings objects
- Type Settings and Definition Settings have an abstract superclass
- Changed property 'default_value' to 'value' for type settings, for consistency
- Updated the above change in database with new update step

Still the settings need to be refactored regarding how the forms are built at some time
Update references to renamed methods "getDefaultValue()" and "setDefaultValue()" removed with last commit
Implement Custom Settings for types and definitions
- Pass custom settings to PDF renderer, e.g. Jasper
- Add GUI for user to list all certificates
- Add GUI for administrators showing certificates of all users ( TODO Permission check based on plugin configuration)
- Refactor Standard Placeholders
Merge branch 'dev' of https://github.com/studer-raimann/Certificate into dev