Ignore control characters

[janbarasek]

Hello,

when entering an input, it can sometimes happen that the user inserts a control character. For example, in the Mac Terminal, just pressing the ESC key will insert the \e character into the string, which is extremely dangerous for further processing.

I think entering values should be treated against entering control characters.

For example, I enter ESC to the mailer_transport constant, which deletes the following character in the XML:

Thanks.

[stof]

This is a good idea. Do you want to contribute such a change ?