Remove space

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>
Prefix private method with double underscore (_) and put prototype under interface in its implementation file

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>
Change the text on "Done" button on challenge selection screen from "Save" to "Done"

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>
Rename WMSoundsListViewController class to WMSoundSelectionViewController class and WMChallengesListViewController class to WMChallengeSelectionViewController class

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>
Rename some variable to make it more meaningful

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>
Fix crash while showing sound selection screen. because cell identifier was not found

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>
Fix crash while showing challenge selection screen. because cell identifier was not found

Signed-off-by: Agustinus Verdy Widyawiradi <verdywid@gmail.com>
Eliminate the need to store selected challenge and sound to NSString, get them from UILabel straight away

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