Adds BlockStyles.

This allows the block to be changed to a certain class.
Adds support for actual class change.
Use the styles from block definition.
Merge branch 'feature/style-blocks'
Adds support for automated removal of empty blocks.
Merge branch 'feature/remove-empty-blocks'
Adds i18n to block level controls.
Adds german localisation.

This also changes the default language to german and implements
requested wording changes.
Merge branch 'feature/better-i18n'