New features

Initial Commit

Another alpha release with the following changes

• Issue #2974917 by jlscott: Provide custom file field class for S3 cors files
• Issue #2973156 by jlscott: Restrict widget to file or image fields using S3 storage
• Issue #2974920 by jlscott: Clean redundant functions from module file
• Issue #2976454 by jlscott: Validate max file size specified in widget

• Issue #2974947 by mferanda: For HTML grid, need to handle multiple headers and improved split and unified field for diff layout
• Issue #2977972 by mferanda: Allow changes to default after initial creation

Initial version.

Added cross-platform support
Removed url from config file
Added toggle UI element
Theme's settings page refactoring.

Dev release