Make use of the scrollto= parameter in activities

Fix #161
Adjust the tests to contain the new parameter
Correctly display the mimetype icon when the preview is not available

Fix #169
Merge pull request #173 from owncloud/stable7-test

Stable7 Backport running the unit tests
Patched french translation (backported from master)
Fixed missing backslash
Merge pull request #184 from zinks-/l10n-fr-backport

Patched french translation (backported from master)
Always prepare parameters for extensions
Merge pull request #194 from owncloud/always-prepare-parameters

Always prepare parameters for extensions
Merge branch 'stable7' of https://github.com/owncloud/activity into stable7