Integration with Dryad as a data portal

[roll]

Overview

# Read from datapackage file (we need to create/find a dataset with datapackage.json)
package = Package("https://datadryad.org/stash/dataset/doi:10.5061%2Fdryad.c866t1g4c")

# Create package from present files
package = Package("https://datadryad.org/stash/dataset/doi:10.5061%2Fdryad.c866t1g4c")

# More requirements will be added
# ...