Refs #113 - Updated icon animation for new notification icons

This MR contains the following changes:

• Construct frameOpacities array based on given animation parameters.
• Updated frame rendering logic to render exactly the frames as defined by frameOpacities rather than one frame for each 10% opacity increment.
• Stopped using notification type-specific icons and instead used "information" icons for all notifications.
• Call animateIcon() only once to allow for a seamless animation without delays between loops.
  • Stop animation after finishing given number of animation loops.
  • Moved stopRequested check into animateIcon().

Note that I'm specifying only six transition frames because the first and last frame of the transition are keyframes which means that there are 100ms on each end of the transition frames which can be considered both keyframes and transition frames.