Change feature default values to something that will be identified as "not set". When a flight is created, features with missing values (not set) are not included. Note that all these are persistent, which may create a problem if something changes (different vehicle with large weight difference for instance). As the subsequent use of these are persistent, a question may not be asked because it's already set (the brief only asks for missing or problem values).

Make the choice of using a personal key persistent. This will allow to toggle between personal and hardcoded key. Otherwise you would need to clear your personal key each time you want to use the hardcoded one.

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

* Export should always be enabled since you can export default tile set
* Fix Select All/None problem

Previously the first activeChanged signal got lost because it was not connected yet to the LinkInterface which resulted in a link incorrectly shown as inactive.