Merge pull request #8 from NilsL/unstable

merge commits
Merge pull request #11 from TaoW/master
Merge branch 'unstable' of https://github.com/NilsL/DMS_Uni_Projekt_PHPMySQL into unstable
code clean up
-added PHPdoc
-deleted insert_file_helper and put code into insert_file
Merge pull request #12 from NilsL/unstable
revert commit f50fbce40f
- if javascript is disabled on user client the validation function
won't work