* rework folder uploading
- flatterns hierarchy on folder upload
- performs a single traversal for the entire folder heirarchy and ends with a comple file list
- allows now dropping folders on existing folders
- overall code improvements
* fix unit tests
* readme updates
* clean old and unused code
* code cleanup
* limit concurrent uploads
* update code as per review
* fix upload button for Safari
* fixes for Safari
- Safari compatibility
- code updates based on review
* fix code
* fix unit tests
* 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
* improved uploading of files
- new core/UploadDirective to allow dropping files to any html element
- enhanced file dropping for DataTable rows (disabled by default)
- enhanced file dropping for DocumentList rows (disabled by default)
- upload drop area now handles file uploads for child elements (i.e.
rows in the document list)
* fix unit tests
* unit tests and code cleanup
* #1732, fix upload of folders
