* Implemented sliders' material lookAndFeel;
* Material lookAndFeel have been applied to sliders;
* Improved UI layout for panel.
* Adjusted positioning of elements during resizing.
* New icon for "Mute" button;

Modified the pngs for the 5th radio button to have a non-edge style.  Additionally I added a 6th button for generating spikes that has a spike waveform.  I don't have the Jucer running locally so I can't add these files to the BinaryData class.

The waveform icons should be made a bit thicker, but otherwise these look cool.

The control panel now holds an "AudioEditor" to adjust volume
and open a window to alter device settings. Audio output is definitely
working, but different buffer sizes make it sound really weird. The
same problem is present in the Juce demo app, however, so I don't
think it's a problem inherent in the GUI.