Big Update

- Edit Option's Move File and Edit ID3 options finally uploaded(missing
back button action)
- Multiple selection of Song objects
- Changes to button layout: This will be temporary. It will only be used
to identify buttons better when debugging.
- SelectedSongs Singleton: Singleton used to access selected songs from
any part of the application!!!!
- Bitbox app Class; Singleton initializer. This way we can create a new
Singleton class everytime we need to access certain objects from
different parts of the app !!!
- Multiple comments added.
- AndroidManifest.xml file modified.
- Layouts modified.