Add Signal Computing: Digital Signals in the Software Domain Book to free-programming-books.md (#5014)

* Add Free and Open Machine Learning book to free-programming-books.md

* Add Resilient Web Design to free-programming-books.md

* Add Lies, Damned Lies, or Statistics: How to Tell the Truth with Statistics Book to free-programming-books.md

* Add Scientific Computing Book to free-programming-books.md

* Add Signal Computing: Digital Signals in the Software Domain Book to free-programming-books.md

free-programming-books.md

@@ -660,6 +660,7 @@
 * [Real-World Maintainable Software](https://www.oreilly.com/ideas/real-world-maintainable-software) - Abraham Marin-Perez
 * [Record-Playback Test Automation: Sahi & Selenium IDE: Critical Evaluation of Record-Playback Automation Tools](https://leanpub.com/manualToAutomatedWithSeleniumIDEAndSahi) - Shashikant Jagtap  *(Leanpub account or valid email requested)*
 * [Scientific Programming and Computer Architecture](https://divakarvi.github.io/bk-spca/spca.html) - Divakar Viswanath
+* [Signal Computing: Digital Signals in the Software Domain](http://faculty.washington.edu/stiber/pubs/Signal-Computing/Signal%20Computing.pdf) - Michael Stiber, Bilin Zhang Stiber, Eric C. Larson (PDF)
 * [Small Memory Software](http://www.smallmemory.com/book.html)
 * [Writing Native Mobile Apps in a Functional Language Succinctly](https://www.syncfusion.com/ebooks/writing_native_mobile_apps_in_a_functional_language_succinctly) - Vassili Kaplan