Add validation
Add licences for the icons
Fixed some design related problems with the windows
Fixed design bug in printing component
Added DateField-style, increased contrast of navigation
Changed hierarchy of StudentMaterialSelector. Closes #388
Merge pull request #403 from jidel/issue#361-redesign_app

Issue#361 redesign app
Refactored StudentMaterialSelector
Fixed input validation
Merge pull request #404 from jidel/issue#381-category_name

Issue#381 category name
added/changed html help files for the views
set Vaadin Label content mode to HTML
defined width and heigth of help window
added styles.css to .gitignore
Integrated EventBus
Merge pull request #405 from davherrmann/issue#402

Issue#402
Merge pull request #407 from davherrmann/issue#406

added styles.css to .gitignore
Merge pull request #408 from jidel/issue#296

Integrated EventBus
Added borrowed until to ManualLending
Changed window header height