Published package compiled files still have `export`

[cinderblock]

Not sure why but looks like the compilation didn't run properly on the published version. The main source files still have export statements which don't work: unpkg.com/rxjs-obd

I think this would be fixed with:

1. Add prepare step #2
2. npm version patch
3. npm publish

(PS, where are 0.0.38-0.0.41 on github?)