Reduce heavy dependencies

[fabiospampinato]

I see the entirety of lodash is being imported, while only a handful of its methods are being used.

Importing only the required methods would be beneficial to bundle size.

[crushjz]

I agree with that! I think it is crucial if the library is used in a front-end app.

[zmitry]

https://github.com/zmitry/graphlib Check this out, it doesn't have this issue.

[darscan]

A PR exists to address this: https://github.com/dagrejs/graphlib/pull/118

[rustedgrail]

Lodash is no longer a dependency for graphlib. As I get to it, I'm removing it from the rest of the libraries.