Merge branch 'master' into dev
Change name of Matrix2D to Transform2D to capture that it involves translations
Move native version of Matrix2D
Rename the `Matrix2D` type to `Transform2D`
Add gray, charcoal, and greyscale
Switch runtime over to Transform2D library
Add the ExtraChecks module to do occurs check and check the type of main
Check that main is a Signal or (Signal Element), add tests for this case
Add occurs check and a test to make sure it works
Merge branch 'dev'