Added support for sequential multi file upload. Fixes #429
Added enqueued status update. Fixes #429
Added observers for preprocessing files (#429)
Merge branch 'development' into multi-file-upload
Implemented queue using Deps.autorun. Work in progress
Implemented queue using Deps.autorun. Work in progress
Fixed wrong username
Implemented queue using Deps.autorun. Work in progress
Implemented sequential file checksum/upload processing
Merge branch 'sha256-custom' into multi-file-upload
Simplified process flow, fixed commented issues
Fixed commented issues, handled checksum computation progress
Fixed wrong comment
Added preprocessing progress updates
Merge branch 'sha256-custom' into multi-file-upload

Conflicts:
	client/import.coffee
Merge branch 'sha256-custom' into multi-file-upload
Just small stylistic changes and comments.
Serialize update and finalize in checksum computation.
Added second progress bar.
Handled preprocessing errors