Merge pull request #66 from ostepu/version_0.1

Version 0.1 II
image names fixed (de.gif, en.gif)
line endings fixed
- install.php stores db_user_operator
- db_user entry in de.ini modified
- blank lines removed
- some ?> added
Merge pull request #70 from ostepu/version_0.1

Version 0.1 III
images for navigation bar added
installer design modified
- "store settings" functionality is disabled
- call by references fixed
button for phpinfo() added
Merge pull request #71 from ostepu/version_0.1

Version 0.1 IV
belongs to #81
belongs to #80
- belongs to #76
- download attachments for lecturers and tutors enabled
belongs to #76
belongs to #75
belongs to #72
belongs to #74
belongs to #76
- belongs to #83
- small changes