Code Repositories Migrated to OSDN

Because Bitbucket will be dropping support for Mercurial, and because I prefer Mercurial to Git, I am migrating all of my open-source repositories to OSDN.  Documentation that is currently hosted on ReadTheDocs (RTD) will also be hosted on OSDN because RTD cannot clone documentation sources from OSDN.

Projects now hosted on OSDN are:

• execsql
• execsql-upsert
• execsql-glossary
• tklayout
• tkpane
• xtab
• un-xtab
• chkcsv

Documentation can be opened from the project pages or directly using URLs of the form http://<project_name>.osdn.io -- e.g., http://execsql.osdn.io/.

Documentation currently on RTD, and repositories on Bitbucket, will be removed sometime prior to the end of May 2020.