Withdraw athlete during weigh-in

[scottgonzalez]

Add ability to withdraw an athlete during weigh-in.

[scottgonzalez]

We could add a new text field, withdrawnFromSession or similar. We'd add a button to the athlete information dialog to withdraw the athlete. Clicking the button would copy the value of their currently assigned session into the new withdrawnFromSession field and then clear out the session field. When this value is set, we can display "(withdrawn from session {withdrawnFromSession})" below the session field.

setGroup() should clear the withdrawnFromSession field.

[jflamy]

Currently removing the athlete from their session will perform a correct withdrawal.
So this is low priority.

[jflamy]

Not needed anymore