Handle options texts with dots

[timolemke]

Based on the workaround in 3082794

Option of a fields with options (e.g. RadioButton) are serialized in the struct-property in this way:

• The options displayName is used as the name of the structProperty
• The default-behaviour-CheckBox and the optional technicalValue of an option are serialized as Boolean- and String-Properties, below the struct-Property

This has historical reasons and is obviously not good: The options displayValue might contain a lot of characters and (which is the worst) might contains dots. This will lead to a bug: the whole option cannot be edited anymore.

A quick solution could be: Escaping the dot
A better solution would be: serializing the displayName in a stringProperty. The old structure must still be readable, otherwise each project has to perform a content-migration...