Merge pull request #2 from uploadcare/develop

New widget API, uShare -> v 1.4.1
Recent Uploads show URLs for uploads from URLs
No more UCUploader (good riddance!)
When the user cancels the file picking operation, the delegate receives a message
Uploading from URL no longer crashes on error
Better doc comments
Pods updated
WidgetExample discontinued
Redundant resources removed
Minor naming improvements in UploadcareKit