Added basic implementation for value parts and the verification of their constraints.
Added handling of erroneous values in constraints for value parts.
Added constraints for numeric values.
Some changes regarding empty constraint implementation.

Added basic definition of converter and converter context classes.
Added basic container and compound part definitions.

Extended unit tests.
Added list part definition.
Added map part definition.
Added basic support for document formats.
Added storage implementation for OrientDB database.
Adjusted settings for publication if library.
Fixed compiler warnings regarding implicit conversions and refrlective calls.
Enhancement of handling of ListPart indices and MapPart keys. Extended unit tests for both part implementations.