Localisation updates from https://translatewiki.net.

Change-Id: Ifa759ed5a33b53b71536e69103d2d2663da31fb1
Update README.md
Update RELEASE-NOTES.md

Fix broken links
Update RELEASE-NOTES-2.0.md

Synce RELEASE-NOTES as a follow up to c7b9b4ffe310e0d339b40bd1668393df5657f24c
Merge branch 'master' of ssh://wmfgerrit/mediawiki/extensions/SemanticMediaWiki
Update RELEASE-NOTES.md

* Fix typo
* Add issue numbers for better reference
Update RELEASE-NOTES-2.0.md

Sync RELEASE-NOTES as a follow up to 75eb30b4fa1c627f146daf424d4c93534418a699
Update RELEASE-NOTES-2.0.md
Bump master to 2.1 alpha