Fix tsconfig

[jasongrout]

Adding the rootDir option means that the output files will be in lib/ instead of lib/src. I also removed the redundant lib settings, given that we now have an es2105 target.

[jasongrout]

(I didn't test the build after making these changes - presumably the automated tests will do that.)

[maartenbreddels]

It gives this error:

error TS6059: File '/Users/maartenbreddels/src/ipysheet/js/package.json' is not under 'rootDir' '/Users/maartenbreddels/src/ipysheet/js/src'. 'rootDir' is expected to contain all source files.

Odd thing is, with ipyvolume it does go to lib, and not lib/src, without this option. Good to know we could get rid of the libs.

[maartenbreddels]

Reading https://github.com/Microsoft/TypeScript/wiki/FAQ#why-does---outdir-moves-output-after-adding-a-new-file for some reasons the longest common prefix in ipyvolume is longer.
Very unnatural behavior I'd say.

[martinRenou]

Thanks Jason, the output files issue was actually due to the json package, I fixed it in #87. Maybe you can remove the rootDir change and only keep the removal of the redundant lib settings?