Batch update changelogs

metadata/ch.blinkenlights.android.vanilla.txt

@@ -3,7 +3,7 @@ License:GPLv3
 Web Site:
 Source Code:https://github.com/vanilla-music/vanilla
 Issue Tracker:https://github.com/vanilla-music/vanilla/issues
-Changelog:https://github.com/vanilla-music/vanilla/commits/master
+Changelog:https://cdn.rawgit.com/vanilla-music/vanilla/master/assets/about.html
 
 Auto Name:Vanilla Music
 Summary:Music player

metadata/com.artifex.mupdfdemo.txt

@@ -3,6 +3,7 @@ License:AGPLv3+
 Web Site:http://mupdf.com
 Source Code:http://git.ghostscript.com/?p=mupdf.git;a=summary
 Issue Tracker:http://bugs.ghostscript.com
+Changelog:http://git.ghostscript.com/?p=mupdf.git;a=blob_plain;f=CHANGES;hb=HEAD
 
 Auto Name:MuPDF
 Summary:Lightweight document viewer

metadata/com.ichi2.anki.txt

@@ -4,6 +4,7 @@ License:GPLv3
 Web Site:https://code.google.com/p/ankidroid/wiki/Index
 Source Code:https://github.com/ankidroid/Anki-Android
 Issue Tracker:https://github.com/ankidroid/Anki-Android/issues
+Changelog:https://ankidroid.org/docs/changelog.html
 
 Auto Name:AnkiDroid
 Summary:A flashcard-based study aid

metadata/jackpal.androidterm.txt

@@ -3,6 +3,7 @@ License:Apache2
 Web Site:https://github.com/jackpal/Android-Terminal-Emulator/wiki
 Source Code:https://github.com/jackpal/Android-Terminal-Emulator
 Issue Tracker:https://github.com/jackpal/Android-Terminal-Emulator/issues
+Changelog:https://github.com/jackpal/Android-Terminal-Emulator/wiki/Recent-Updates
 
 Auto Name:Terminal Emulator
 Summary:Communicate with the shell

metadata/org.billthefarmer.tuner.txt

@@ -3,6 +3,7 @@ License:GPLv3
 Web Site:https://github.com/billthefarmer/tuner/wiki
 Source Code:https://github.com/billthefarmer/tuner
 Issue Tracker:https://github.com/billthefarmer/tuner/issues
+Changelog:https://github.com/billthefarmer/tuner/releases
 
 Auto Name:Tuner
 Summary:Musical instrument pitch tuning