fix some 404 links

Author: SethTisue

_sips/sips/2011-10-12-implicit-classes.md

@@ -11,7 +11,7 @@ redirect_from: /sips/pending/implicit-classes.html
 
 This SIP is based on [this pre-draft](https://docs.google.com/document/d/1k-aGAGmbrDB-2pJ3uDPpHVKno6p-XbnkVHDc07zPrzQ/edit?hl=en_US).
 
-Material adapted from [https://jorgeortiz85.github.com/ImplicitClassSIP.xhtml](https://jorgeortiz85.github.com/ImplicitClassSIP.xhtml)  which is Copyright © 2009, Jorge Ortiz and David Hall
+Material adapted from [https://jorgeortiz85.github.io/ImplicitClassSIP.xhtml](https://jorgeortiz85.github.io/ImplicitClassSIP.xhtml)  which is Copyright © 2009, Jorge Ortiz and David Hall
 
 ## Abstract ##
 

_sips/sips/2012-01-21-futures-promises.md

@@ -721,7 +721,7 @@ Examples:
 5. [Scalaz Futures][5]
 
   [1]: https://www.microsoft.com/download/en/details.aspx?id=19957 "NETAsync"
-  [2]: https://twitter.github.com/scala_school/finagle.html "Finagle"
+  [2]: https://twitter.github.io/scala_school/finagle.html "Finagle"
   [3]: https://doc.akka.io/docs/akka/current/futures.html "AkkaFutures"
   [4]: https://web.archive.org/web/20140814211520/https://www.scala-lang.org/api/2.9.3/scala/actors/Future.html "SActorsFutures"
   [5]: https://code.google.com/p/scalaz/ "Scalaz"

learn.md

@@ -58,4 +58,4 @@ You can visit his [YouTube channel](https://www.youtube.com/user/DrMarkCLewis/fe
 [DevInsideYou](https://youtube.com/devinsideyou) is a YouTube channel with hundreds of hours of free Scala content.
 
 ## Visual Scala Reference
-[Visual Scala Reference](https://superruzafa.github.com/visual-scala-reference/), a guide to visually learn about Scala concepts and functions.
+[Visual Scala Reference](https://superruzafa.github.io/visual-scala-reference/), a guide to visually learn about Scala concepts and functions.