Update dead links and replace if new ones exist (#3390)

* Remove dead link from free-programming-books-tr.md

* Change Django heading to same size as other headings

* Update dead links

* revert django heading level

django is a subheading because it's a Python framework - see the outline, and note the alphabetization.

free-podcasts-screencasts-en.md

@@ -73,7 +73,7 @@
 * [Linear Digressions](http://www.lineardigressions.com) (podcast)
 * [O'Reilly Data Show Podcast](https://www.oreilly.com/topics/oreilly-data-show-podcast) (podcast)
 * [Partially Derivative](http://partiallyderivative.com) (podcast)
-* [Super Data Science](https://www.superdatascience.com/podcast/) (podcast) 
+* [Super Data Science](https://www.superdatascience.com/podcast/) (podcast)
 * [Talking Machines](http://www.thetalkingmachines.com) (podcast)
 
 
@@ -148,7 +148,6 @@
 
 #### Angular.js
 
-* [Adventures in Angular - DevChat.tv](https://devchat.tv/adventures-in-angular/) (podcast)
 * [Angular Air](https://angularair.com) (podcast)
 
 
@@ -203,7 +202,7 @@
 * [Developer Tea](https://developertea.com) (podcast)
 * [DevelopersHangout](http://www.developershangout.io) (podcast)
 * [FLOSS WEEKLY](https://twit.tv/shows/floss-weekly) (podcast)
-* [Frontside the Podcast](https://frontsidethepodcast.simplecast.fm) (podcast)
+* [Frontside the Podcast](https://frontside.io/podcast/) (podcast)
 * [Full Stack Radio](http://www.fullstackradio.com) (podcast)
 * [Functional Geekery](https://www.functionalgeekery.com) (podcast)
 * [Garbage](http://garbage.fm) (podcast)