* upload feature rework
lots of improvements for upload dialog and underlying services
* readme update
- readme cleanup
- remove some old comments from code
- update readme with new events for Upload Service
* restore prerequisites section in readme
Various upload dialog improvements
- fix: headers alignment
- fix: Name column alignment
- fix: rename ‘CANCEL’ button to ‘Cancel all’ (as it’s what it does)
- fix: ‘Cancel all’ button still visible after all upload complete
- new: improved layout and api for file upload components
- new: strongly typed methods for UploadService