Add arcing tools to Canvas

Again I believe this should be in an upgraded Sentence diagrammer with the option to export to Canvas.

@mjespuiva-86 Our hope is to retire Sentence Diagrammer and bring all of its functionality into Canvas. Not sure if/when we'll get around to it, but it seems like consolidating would benefit both.

@phil-gons Having spent spent several decades upgrading my sentence diagramming software as different universities made significant improvements to the technology, I strongly disagree with the intent to use Canvas. Logos should be moving into the more automated software not retaining the more manual approach that has hindered the use of the current software. If you wish to move the output of the automated tools into Canvas as a display means, that would be reasonable as the output of a solid sentence diagrammer can often be a piece of a larger visual project.

BTW I am not impressed with the functionality of the current sentence diagrammer - if lacks the basics of auto-adjustments of angles in tree diagrams, basic alignment and centering, . . .