Changes to imageCropper, supports new mediafilesystem
Fix U4-4119 - Export Fails for Generic Properties

Adds null checking for PropertyGroupID on export so that properties with
no group (tab) don't throw an exception.
PackageService: Fixes Single import for DataTypes

Importing a file with a single data type failed, because the DataType
element is at the root when exported.
Merge pull request #298 from KevinJump/6.2.0--PackageServiceFixes

6.2.0  package service fixes
Merge pull request #270 from stefana99/6.2.0-imagecropper

Changes to imageCropper, supports new mediafilesystem
Finalizes: U4-4472 Image cropper should use IFileSystem - currently uses standard IO
Merge remote-tracking branch 'origin/6.2.0' into 7.1.0

Conflicts:
	src/Umbraco.Core/Services/PackagingService.cs