Bug fixes

Initial Alpha release.

Hotfix for regression with Layout builder.

GridStack 8.x-2.0-dev, 2019-03-20
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- Added .gridstack--nested class for easy styling with nested grids.
- Moved entity-related methods to GridStack entity.

Issue #3041563 by mikelutz: Repository Housekeeping
Issue #3040654 by mikelutz, AngryWookie: Overridden fields set to NULL if not present in source
Revert "Issue #3040654 by mikelutz, AngryWookie: Overridden fields set to NULL if not present in source"
This reverts commit 01e3e7b6b8ca0ce9a005977dab8a9fd837ba231d.

Fix :
Coordinates are inverted

• Lots of coding standards fixes.
• Issue 3040227 - Use dependency injection
• Issue 3036817 - Update wording when Debug is enabled
• Issue 3035322 - Linked files will download if querystring present