Adding "requireUploadMetaData" option.

Adds a proper error message for when the internet connection goes offline and the assembly returns REQUEST_ABORTED.

Fixes a problem of unnecessary file input field clones in case of XHR uploads.

Adding more logging for S3 and JSONP errors.

Minor bug fixes and improvements and progress bar design change.

Emit onResult() for the same file id if it is re-used across different steps. This is an important patch for the previous buggy 2.6.1 release.

This contains an important bugfix for 2.6.0, but has problems itself. Please do not use this release, please use v2.6.2 or newer.

Introducing the tracking of upload and result file IDs.

This is to trigger the onUpload() and onResult() callbacks without the need to rely on the API to give us the new uploads and results in subsequent status polls with the "seq" query parameter.

This adds support for internationalization of used strings (thanks to @jbourassa)

Improves logging for ASSEMBLY_NOT_FOUND errors.