Sayonara subgraphs

Gets rid of subgraphs, opting for a purely event-based syntax.

Capable canvas

Adds the ability to manipulate the canvas via Draw2D.

Containable compilation

Makes builds faster by splitting up code-gen'd files.

Incisive inception

Fixes a nested pursx namespace-collision bug.

Smashing subgraphs

Removes the env parameter from the subgraphs, as it was not used and is always replaceable by something else.

Ebullient events

Uses the revamped event library for fun and profit!

Fateful failures

Tears down the failed experiment of existentially-scoped events. But I learned something! Don't create existentially-scoped events :-D

Phenomenal phantoms

Uses phantom types on events, which restricts them to the correct scope.

Phantasmagoric phantom

Removes an unnecessary phantom type.

Erudite existentials

Uses existential types for subgraph construction.