Take a mock exam!

1376517119_label_new red Mock exam (test level 1 only for now) exercise added.
1376517119_label_new red Two new voices are available, change the default voice using the Options charm.
1376517119_label_new red Each time you re-play a sound, a different voice is used.
1376517119_label_new red A traditional song is played in background of the menu page (can be disabled from the options charm).
1376517417_57 Potential instability fixed, was capable to crash the app.
1376517417_57 Problem to output the sound under some winRT & windows 8 devices fixed.
1376517417_57 Improved statistics page.