-Redesigned Player fragment
-Made global changes to colors, increasing contrast and ease of reading.
-Made some layout changes to list rows to try and minimize unnecessary
information.
-The app now loads the track that was played last upon starting, so the
player fragment should only look "empty" on first startup.
-Added custom class for ToggleButton with image drawables that adhere to
padding rules.
-Added custom View object called PullRefreshLayout, that only listens to
pull gestures at the top of the screen.
-Cleaned up package structure and xml resources