Added support for NanoDrop task.

Files to be loaded into the NanoDrop machine are downloadable.
Files from the NanoDrop machine can be uploaded.
Data is currently not attached to the plate.
Enable rack scan to be used as a 2nd step
Remap NanoDrop file structure for updates.

Added _.restructure to remap an object to another structure.
Use the above to remap the NanoDrop file to plate.update structure.
Merge pull request #294 from mattdenner/nanodrop_support

Nanodrop support