4.0.0

See full CHANGELOG

• Form nows register element class, instead of using hardcoded string.
• Form has new registerType method to register new custom elements. getType(string $name) and getTypes() can be used to get the class for a type (eg. 'text', 'select', etc.) abd a list of types. removeType will unregister a type.
• Form still fallback to Text type if type is not found, but this can now be changed with getDefaultType and setDefaultType.
• Form uses RequestSchemaRepository instead of RequestSchemaInterface.
• Stricter PHP7 type throughout.
• Renamed BaseInput to Input.
• Input has new setValue, getElement, setElement, getName & setName methods.
• Checkbox element now pass the value to non-binary checkbox.
• FormGeneratorController uses strict typing.
• Finished tests and fix tests namespace. 100% coverage!
• Added PHP-CS-Fixer, PHPStan, StyleCI configuration.
• Updated Travis setup.