Terminaltexteffects

* blackhole radius is based on the canvas size, not the input text size.

* motion.Motion.find_points_on_circle and motion.Motion.find_points_in_circle now account for the terminal character height/width ratio to
return points that more closely approximate a circle. All effects which use these functions have been updated to account for this change.

* Updated documentation

* Fixed Gradient creating two more steps than specified.
* Fixed waypoint synced animation index out of range error.

* Fixed animating_chars filter in effect_template to properly remove completed characters.
* Initial symbol assignment when activating a scene no longer increases played_frames count.
* Waypoints and Animations completed are deactivated to prevent repeated event triggering.
* Fixed step_animation in graphics module handling of looping animations. It will no longer deactivate the animation.

* Fixed inactive characters in expand effect.