Mood bar

This is a fix for the MOOD BAR waveform overview mentioned in https://bugs.launchpad.net/mixxx/+bug/1074392
I have added woverviewmb.h , woverviewmb.cpp files where the waveform drawing will happen. I add a line in dlgprefcontrols.cpp files to add MoodBar option to woverviewcombobox. I also added some lines to skin/legacyskinparser.cpp file to say what to do if MoodBar option is selected in the combobox. I added woverviewmb.cpp file to the build/depends.py. These are the changes I've made.

MoodBar is tested with tracks and work fine. Moodbar is still in the child stage but hope to continue developing it to enhance feature extraction and mood detection.

by a mistake I have added some files related with QtCreator project management and I have removed them so only necessary files are now there. This is my first attempt to get involve in mixxx developer family and I'm quite new to developing opensource projects so If I have done something wrong please mention.

Best regards,
Udara.