Update changelog.txt

no problem for the login page, i fixed my name. ;)
Merge pull request #1180 from sfahrenholz/patch-2

Update changelog.txt
Update acknowledgements.txt

add Sebastian Fahrenholz
Merge pull request #1181 from sfahrenholz/patch-3

Update acknowledgements.txt
Removed some TODO's
Enforced current metadata size limitations
Fixed SQL typo
Merge branch 'master' of github.com:duplicati/duplicati
Merge branch 'master' into metadata