Don't override fs module

[ikokostya]

Problem

Now node-fs-ext overrides fs module, i.e. adds new constants to it. Because Node.js modules are cached, other modules got implicitly redefined fs module.

Also, since Node.js 11 constants are not extensible anymore #76 and deprecated since Node.js 6. So, there is no way to get them in new versions of Node.js (only import binding file directly).

Proposal

Instead node-fs-ext can export own constants and doesn't touch core fs module:

const {fcntl, constants} = require('fs-ext');

fs.fcntl(fd, constants.F_SETLK, constants.F_WRLCK, (err) => { ... }); 

Related Issues

#81

[baudehlo]

I agree completely. It made sense at the time, but Node has matured a lot.

However someone else is going to have to create a PR that does this.

[ikokostya]

However someone else is going to have to create a PR that does this.

I created PR #90. Please take a look.