Update to 3Dmol 2.0, now directly compatible with TypeScript

[ceriottm]

You have asked to break this, and your wish has been granted. When I try to load the azaphenacene example, the npm server crashes and gives the error

<e> [webpack-dev-middleware] ModuleNotFoundError: Module not found: Error: Can't resolve '/home/michele/lavoro/code/chemiscope/node_modules/ts-loader/dist/stringify-loader.js' in '/home/michele/lavoro/code/chemiscope/src/structure'
<e>     at /home/michele/lavoro/code/chemiscope/node_modules/webpack/lib/Compilation.js:2017:28
<e>     at /home/michele/lavoro/code/chemiscope/node_modules/webpack/lib/NormalModuleFactory.js:817:13
<e>     at eval (eval at create (/home/michele/lavoro/code/chemiscope/node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:10:1)
<e>     at /home/michele/lavoro/code/chemiscope/node_modules/webpack/lib/NormalModuleFactory.js:275:22
<e>     at eval (eval at create (/home/michele/lavoro/code/chemiscope/node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:9:1)
<e>     at /home/michele/lavoro/code/chemiscope/node_modules/webpack/lib/NormalModuleFactory.js:448:22
<e>     at /home/michele/lavoro/code/chemiscope/node_modules/webpack/lib/NormalModuleFactory.js:122:11
<e>     at /home/michele/lavoro/code/chemiscope/node_modules/webpack/lib/NormalModuleFactory.js:654:23
<e>     at /home/michele/lavoro/code/chemiscope/node_modules/neo-async/async.js:2830:7
<e>     at done (/home/michele/lavoro/code/chemiscope/node_modules/neo-async/async.js:2925:13)
<e> resolve '/home/michele/lavoro/code/chemiscope/node_modules/ts-loader/dist/stringify-loader.js' in '/home/michele/lavoro/code/chemiscope/src/structure'
<e>   using description file: /home/michele/lavoro/code/chemiscope/package.json (relative path: ./src/structure)
<e>     using description file: /home/michele/lavoro/code/chemiscope/package.json (relative path: ./node_modules/ts-loader/dist/stringify-loader.js)
<e>       no extension
<e>         /home/michele/lavoro/code/chemiscope/node_modules/ts-loader/dist/stringify-loader.js doesn't exist
<e>       .js
<e>         /home/michele/lavoro/code/chemiscope/node_modules/ts-loader/dist/stringify-loader.js.js doesn't exist
<e>       as directory
<e>         /home/michele/lavoro/code/chemiscope/node_modules/ts-loader/dist/stringify-loader.js doesn't exist

[Luthaf]

I'm seeing a lot of changes that I can't quite follow -- can you give some insight into the API changes that necessitated these code changes?

The API changes are minimal, mainly different types declaration and index now being an actual field for AtomSpec.

I also took the opportunuity to cleanup some of the code surrounding the grid and viewer classes.

[ceriottm]

Played a bit more with it, also on the jupyter side, and all seems in good order.