added release note
### Version 0.0.20 ###
## Common
+* Plates have been renamed
+ * This was done primarily because we were using the term incorrectly, since Dynamic Bayes Nets (e.g. Hidden Markov) are not Plates.
+ * `Plates` --> `Sequence`
+ * `Plate` --> `SequenceItem`
+ * `plate` package --> `template`
* Saving a network as a DOT file includes labels on constant vertices.
## Python
