<DE2 Database> Added loadSongsFromSD function

This function will read all songs in .wav format from SD and write it in
a file, with a specific format.
Songs are going to be stored with the following text format:
1 SONG.WAV
2 ANOTHERSONG.WAV
3 SONG4.WAV
etc.
<DE2 Database> Fixed some bugs in loadSongsFromSD

works fine now. we can open the TXT file and see all the wav files :]