Tunni+speedvis+cut (#392)

* Added speed visualization.

* Added tunni line and point manipulation.

* Forgot a file with the last commit.

* Refactored the measure tool to be similar to Inkscape's.

* Changes to accomodate for MFEKmath changes.

* Added a cut tool.

* Changes to the menu and tool bars to toggle new features. Icon for Cut.

* Development lines uncommented in Cargo.toml/lock will change and rebuild before merge.

* fix build

* Development lines uncommented in Cargo.toml/lock will change and rebuild before merge.

* rebase on top of master

* cargo fmt

* Removed debug prints.

* Fixed black screen.

* Removed warnings. Added missing flush call.

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Co-authored-by: Fredrick Brennan <copypaste@kittens.ph>