Logo size for Login and Register page was reduced
'Maxlength' attribute was removed from data input fields
File-author and -topic are no required fields anymore; 'maxlength' attribute of those fields was also removed
Merge branch 'dev' into feature_upload

Conflicts:
	src/main/java/de/fau/osr/amos/docmatic/FileUploadPage.html
Empty data in the input fields is getting saved as 'NULL' in the database
Download file implemented
Fix file list header repeating
Let user delete a file
Merge branch 'feature_implementMockup' into dev
Merge branch 'feature_upload' into dev
Merge branch 'dev'
add display image
add image for diaplaying uploaded list