Ui enhancements from platform overview on 8/23

[shreyapandit]

• Center page when starting to record reference because no canvas should show up at that point. Show an empty canvas with the text "The reference will play her as its being recorded."
• Add exercise name on a separate line because if its too long it wraps (Settings page)
• During an exercise, change formatting
  ExName (without an s)
  Set 1 of 2
  3 Repetitions
  1 -> commonBlue color
  reps completed
• Add a spinner (Ladda) to the exercise workflow to while data is being saved/loaded
• Change the settings page to be called "Link Users"

[saurabh21289]

PR for the ladda spinner/loader: #107