replace invalids by their default value

[stefraynaud]

How about an option to replace all invalid entries, as reported by a validator, by their default value if specified. A warning may be issued in such case.
The option may take the form of an improvement of the current 'invalid' option that is currently implemented in Pull Request #135

[robdennis]

this reads as a good idea that's beyond the scope of what I can do in 5.1.0; putting it on "Someday"