Test importing and usability of packed library

[mlhaufe]

A few times now after the package is built and published it throws a type error once imported by clients. Thus far this has been due to *.d.ts files not being included in the package.

A means of checking for this problem before publication is desired.

Use the standard Stack implementation to test?

1. npm pack
2. npm init a subfolder with Stack implementation
3. npm install dependency from local file package
4. check for errors