Add validation error messaging in Bootstrap and Foundation components

[udos86]

Will arrive in 1.1.0

[udos86]

@DavyJohnes: Please have look at 94ee42b.

[DavyJohnes]

@udos86 I think we need to find a way to define error messages mapping once for the whole form and add ability to override it for particular controls in model. I believe in most scenarios messages patterns will be the same for each control across all forms. Current implementation forces to define error messages for each control, I think it is redundant.
May be it is necessary to introduce new form model class which will cover all these things? Something like that:

class FormModel {
    public options: FormOptions;
    public controls: Array<DynamicFormControlModel>;
}

class FormOptions {
    public errorMessages;
    // ... other form-global options.
}

[DavyJohnes]

Added one more comment here: 94ee42b
Everything else looks good, thanks for your work!

[udos86]

@DavyJohnes Thanks for the great contribution! I'd like to avoid reintroducing a DynamicFormModel class as this would make the library more complex to use.

And I strongly believe, error messages should be set for single DynamicFormValueControlModels. This ensures that error messaging is only enabled when the errorMessages object is explicitly set on the model. It provides more freedom of choice as it allows individual messages for every control and the message templates are also included in the JSON serialization. Applying it to the entire form, however, would be just an assumption.

As a developer, having to manually override a framework's wrong assumption in order to generate individual messages for a single control is not ideal from an architectural point of view.