Start documenting client-side hooks and improve the value passed to the before callback.
Document success/failure cases and fix obvious bug in the failure handling code.
Wordsmithing.
Add submit callback function and docs on preventing the form submission until the upload is complete.
Use the url as a namespace for the serialization.
Update usage of the signing/serialization utils to use the url as the namespace.
Test case to assert that widget will not use value from a different upload url.
Release note on security issue.
Merge branch '1-client-side-hooks'
Change release version and add note on plugin documentation.
Remove trailing whitespace.
Bump version number and set release date.