[ChangeLog] Fix typos and add unreleased version header

ChangeLog

@@ -1,3 +1,6 @@
+version <unreleased>
+
+
 version 2016.10.19
 
 Core
@@ -7,8 +10,8 @@ Core
 
 Extractors
 * [vidzi] Fix extraction (#10908, #10952)
-* [urplay] Fix subtitle extraction
+* [urplay] Fix subtitles extraction
-+ [urplay] Add supprt for urskola.se (#10915)
++ [urplay] Add support for urskola.se (#10915)
 + [orf] Add subtitles support (#10939)
 * [youtube] Fix --no-playlist behavior for youtu.be/id URLs (#10896)
 * [nrk] Relax URL regular expression (#10928)