Update ellipsis function and add it to Spline

# Add Ellipsis function as a core utility

Status: **Opened for visibility**
Reviewers: @jeffkamo @ry5n @mediumjones 

## Changes
- Fixed syntax error in Ellipsis function as noted by #18 
- Added `ellipsis` as a function to the core Spline import
- Removed the ability to specify whether text should wrap in Ellipsis because wrapping didn't work anyways
- Add a visual test for Ellipsis

## Notes
- Fixes #18