fix image sizes for pdf
Merge pull request #367 from owncloud/fix-image-sizes-pdf

Fix image sizes pdf. Fixes #250
Installation wizard / database hint consolidation & fixes

Conflicts:
	admin_manual/configuration/configuration_database.rst
	admin_manual/installation/installation_source.rst
Fixes according to MorrisJobke's comments
Add wizard page to index, trusted_domain hint
Crop images
Adapt img resolution to avoid size warning
Merge branch 'master' of github.com:owncloud/documentation into random-typos
more updates, as suggested.