Fix multiple alphabet song sounds playing.
Removed stale TODO comment
Merge pull request #21 from CS673/vivek-sound-fix

Fix multiple alphabet song sounds playing.
Merge branch 'master' of https://github.com/CS673/Awesome-Alphabet.git
Created IThemeControllerView interface and renamed ThemesPageController
to ThemeController.  Also, added setCurrentTheme() function to
ThemeController.