Improve responsiveness of control buttons #6
Description
Right now the three center buttons (shuffle/play/repeat) have a significant delay when pressed before updating to the state actually reflected in Spotify. This is despite the fact that Spotify responds much, much more quickly than the button's state is actually updated, so if you have music playing and pause it, it'll be a few seconds before FantasyPlayer's play/pause button actually reflects the correct state despite Spotify having stopped playing the music already.
I'm unsure if this delay is due to the responsiveness of the API, but if it is it may be something worth considering to have FantasyPlayer change the button state immediately based on what the next button state is (eg. if you press the Play icon it turns into the Pause icon immediately), and then update based on what the API returns (in order to prevent state desyncs). This would improve the apparent responsiveness.