node core libs with promises and better errors

Currently just fs is supported.

npm install --save newcore

fs

Example:

var fs = require('newcore/lib/fs');

fs.readFile('lorem.txt', 'utf-8')
.then((text) => {
  console.log(text);
})

// selective error handling
.catch(fs.errors.NotFound, () => {
  console.log('File lorem.txt is missing');
});

Errors:

Code	Error Name
EACCES	fs.errros.PermissionDenied
EEXIST	fs.errors.FileExists
EISDIR	fs.errors.IsDirectory
ENOTDIR	fs.errors.NotDirectory
ENOTEMPTY	fs.errors.NotEmptyDirectory
ENOENT	fs.errors.NotFound
EMFILE	fs.errors.OutOfFileDescriptors
EPERM	fs.errors.Permissions

TODO

Add all of the apis mentioned here nodejs/node#5020