there is also a small software call Go Play Along (http://www.goplayalong.com/) It allows to play a tablature from guitar pro with the MP3 in background, with some tools to help to synchronize the mp3 to the tab. You can also decrease the music speed, ...
In RS2012, above 100% you had access to master mode where all notes were hidden. Now, in RS2014 ... the master mode is split per section. So you can have partially the master mode on some part you are playing very well. So the mastery the percentage of the song you already play in master mode. 100% mastery is the same than the RS2012 Master mode (all notes hidden)