Completely rework Auxio's iconography based on the new material symbols
icon set.
This does the following:
1. Switches the sharp + filled icon style to an outlined + round icon
style.
2. Removes 32dp icons from everywhere except the playback panel.
This does not:
1. Actually handle optical sizes right. This is going to take some more
work to make it harmonious with the current UI.
2. Update margins in some places to be harmonious with the new icons.
This is also going to take some more work to do properly.
Use Slider and FloatingActionbutton in the playback view. This is not
because I wanted to, but because there were insane bugs on Lollipop
devices that stemmed from them being unable to load complex selector
resources.
