add orgtbl-aggregate, orgtbl-join, orgtbl-fit (#531)

Co-authored-by: Jonathan Lai <[email protected]>

Author: tbanel

README.org

@@ -938,6 +938,9 @@ External Guides:
       - [[https://github.com/ichernyshovvv/org-timeblock][org-timeblock]] — Interactive multiple-day timeblock view for orgmode tasks.
       - [[https://github.com/positron-solutions/dslide][dslide]] - Programmable presentation for org documents
       - [[https://github.com/kickingvegas/casual/blob/main/docs/agenda.org][Casual Agenda]] - a Transient user interface for Org Agenda. Included in [[https://github.com/kickingvegas/casual][Casual]].
+      - [[https://github.com/tbanel/orgaggregate][orgtbl-aggregate]] - Create aggregated table from source table
+      - [[https://github.com/tbanel/orgtbljoin][orgtbl-join]] - Enrich a table with material from other tables
+      - [[https://github.com/tbanel/orgtblfit][orgtbl-fit]] - Do regression fitting on Org Mode tables 
 
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