In the meantime... Your iRealb files can be exported as MusicXML. You can then open them in music notation software and add your melody lines. MuseScore, for example, is a free program: http://musescore.org/
also you can use PDF viewer apps on your tablet to view your notated charts. There is a slightly related thread here: https://forums.irealpro.com/threads/Multitasking-using-Player.1124/
(one day I should update it.) You can use iReal b in the background for practice or live use, or as a source of the chords (described in the previous post by DaleMac) as a basis for adding your notation.