Put a method to validate sound of alarm entity

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>
Put a method to validate challenge of alarm entity

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>
Refactor the way how error message (NSError) is shown

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>
Fix the error message (NSError) construction

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>
Fix core data context won't revert when saving failed and move the update code to notification when saving is successful

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>
Remove view dismissal code upon after updating alarm activation

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>