gganimate 1.0.8

• Fix a bug when creating labels from aesthetics that include glue expressions
  (#422)
• Fix a bug in ffmpeg detection (#346, @rfaelens, #360, @adamdsmith)
• Remove plyr dependency
• Fix a bug in transition_filter() in the presence of NA filter values
  (#404, @rsaporta)
• Fix a bug with static layers that include position adjustments (#418)
• Fix a bug in transition_time() where multiple time values in the same frame
  would lead to unexpected stacking of the data (#414)
• Fix a bug in transition_reveal() where coinciding tweens would result in
  wrong direction of the arrow (#409)
• Fix a bug in transition_layer() when the last layer had an exit duration
  (#384)
• Fix a bug in transition_time() when facets had data with different starting
  time (#357)
• Make sure exclude_layer in view_*() is taken into account
• Fix a bug when using a view with coord_flip() which would result in weird
  flickering and movement of the position guies (#336)
• Fix a bug in transition_reveal() that would require input to be ordered
  along the time dimension for point-like geoms (#323)
• Fix a bug in view_follow() that would result in errors when used with
  discrete scales (#304)
• Fix bug in transition_states() where too few frames relative to states in
  combination with wrap = FALSE would cause an error (#301)
• Fix a bug in transition_time() when the time dimension contained NA values
  (#307)