Fix ajax operation

[rabauss]

This is a follow up of #200 and fixes #197

• Set the correct empty value on execute post actions
• Set the correct parameter types
• Cast the database value to string for equal comparison.
• Update example for toggle published

[qzminski]

Looks good to me. I hope you tested it 🙂

@Toflar @aschempp would you like to throw your two cents in before merging?

[qzminski]

Released as 5.1.7, thank you @rabauss !