commonjs export issue is not fixed completely

[andreo-k]

Subject of the issue

There are fixes in 'development' branch which try to fix commonjs export issue (you assign scope.GridStackUI there). However there is still issue

currently:
try { GridStackUI = require('gridstack'); } catch (e) {}

should be added (in bold)
try { GridStackUI = require('gridstack').GridStackUI; } catch (e) {}

Pls see the fix in my fork of the project
https://github.com/andreo-k/gridstack.js
branch v0.4.0-fix-exports

Your environment

• 0.4.0 and latest 'development' branch
• latest chrome and firefox

Steps to reproduce

1. Build application with webpack with disabled AMD ({ parser: { amd: false } })
2. Try to run application

Expected behaviour

Application runs fine

Actual behaviour

Application fails with 'can not get registerPlugin of undefined'

[radiolips]

Hey @andreo-k ! Could you put in a PR for this update?