Write up first draft of the 0.10 changelog

CHANGES.md

+0.10
+----
+
+A major release, introducing a new user interface (TUI). Special thanks go to
+@mruwek for helping out to get this UI in its current shape.
+
+* New: A column-based user interface. Each column has its own filters and sort
+  order, allowing you to build a dashboard with your todo items. Launch with
+  `topydo columns`.
+* New: color blocks that change from green to red (overdue) as time passes by.
+  Use the %z placeholder to add color blocks to the `ls` output.
+* New: color option can be set to 0, 1, 16 or 256 and if needed overridden by
+  -C on the commandline.
+* New: recurrence based on business days. Skips Saturdays and Sundays when
+  calculating the next date (thanks to @mruwek).
+* New: items can be sorted by length (use 'length' as sort field).
+* New: parents-of and children-of operators with `add`, `dep` and `append`
+  subcommands. The todo item receives the same parents/children from the
+  specified todo item.
+* New: `append` understands relative dates and other tags that are special to
+  `add` (thanks to @rameshg87).
+
+* Fix: dependency ID creation with orphan todo items.
+* Fix: crash after completing/deleting an edited item.
+* Fix: crash after completing an item that got a new dependency with `dep add`
+
+* Change: a new tag value with an existing key can be added with the tag
+  subcommand (thanks to @MinchinWeb)
+* Change: ~/.config/topydo/config can be used as a configuration file.
+* Change: No backups are written for read-only commands (e.g. lsprj)
+* Change: topydo is more scalable for large todo.txt files.
+
+* Known issue: color blocks are not shown in `ls` output in the column UI.
+
 0.9
 ---