mol-plugin: 1st prototype

src/apps/viewer/index.html

src/apps/viewer/index.ts

...geo/representation/structure/visual/polymer-trace-mesh.ts

src/mol-plugin/context.ts

src/mol-plugin/index.ts

src/mol-plugin/state/base.ts

src/mol-plugin/state/objects.ts

src/mol-plugin/state/transforms.ts

src/mol-plugin/state/transforms/data.ts

src/mol-plugin/state/transforms/model.ts

src/mol-plugin/state/transforms/visuals.ts

src/mol-plugin/ui/controls.tsx

src/mol-plugin/ui/plugin.tsx

src/mol-plugin/ui/tree.tsx

src/mol-plugin/ui/viewport.tsx

src/mol-state/object.ts