v1.0.0-rc3

Overhauls what is published to Zenodo and how (see the new zenodo.py module):

• Converts datapackage.yaml to JSON and injects the release timestamp (created), DOI (id), and range of measurement dates (temporalCoverage)
• Creates a custom README.md from an extract of the GitHub README.md, descriptions of the table columns (generated from datapackage.yaml), and the release version, date, and DOI
• Includes all data (data/*.csv) and the LICENSE.md, but all other files in the repository are excluded
• Publishes to Zenodo using their API rather than relying on the default GitHub-Zenodo integration

Improves the organization of the repository:

• Moves scripts (/scripts) to a glenglat.py module in the root directory
• Adds a Jupyter notebook tutorial (tutorial.ipynb) for reading data into Python and producing statistics and plots