Support requiring a specific export

[dantman]

Like "aliases" I think preferences should have a spot for requiring a specific exported method/class.

For example something like this in preferences:

"export": {
  "util": {
    "format": "fmt"
  }
}

Would add to the dialog a "util:format" that would export [var ]fmt = require('util').format.

[ganemone]

This might be better solved with #26

[dantman]

I think the implemented result should probably be a fusion of both.

#26 works implicitly and with multiple variables. However it fails if exports are not defined in-file. And it doesn't provide a way to alias variable names.

So I think #23 would end up as an extension to #26 that allows you to A) alias variable names, and B) add extra variable names when they cannot be extracted from the module.

[ganemone]

I can get down with that