implemented folder stroage allowing unlimited names
adopted delete method. may be harmful in the current state, make backups if testing at production system.
converted uploadAsync method from a mixture of english and german to
plain english
translated upload from mixture of english and german to plain english
simplified file name examination using pathinfo method. removed useless
code, replaced undefined variables ($desc and $tags)
altered uploadAsync, such that title is set to the original file name
while actual storage name is umlaut-safe, altered view templates do
display original names.
moved replacements of umlauts and non-alphabetic characters to clean
method. now also supporting uppercase umlauts.
re-worked folder creation/deletion: folders in the file system are now
created according to the pattern <folder_id>.<filtered name> while in
the web frontend the original names for files and folders are displayed
(allowing virtually every character and spaces)
Implemented security feature in getFolder method: will return false, if
no database entry for the passed folder id is found. this is especially
important, if you try to delete the same folder twice by ajax requests.

The former version returned null. Some functions searched for subfolders
usng this null and returned all folders, which in turn is very bad, if
you wanted to delete a certain folder and its subfolders and instead
delete all folders of all projects (this happened to me!)

This version:
-is safe (accidential removal of all folders is prevented)
-allows multiple folders having the same name at different paths in a
project (it was not possible to have A/Foo and B/Foo, as the would be in
the same physical location)
-allows to give folders and files proper names (containing whitespaces
and symbols characters) while being stored as safe and unique names on
the physical device
adapted export function to new folder layout
added archive download compatibility code for files and folders created
sith older versions
fixed a quotation-related bug introduced in the previous version
Merge branch 'master' into unicode-filenames

Conflicts:
	include/class.datei.php
	templates/standard/fileview.tpl
Merge branch 'userform-correction' into unicode-filenames
Merge branch 'master' into unicode-filenames

Conflicts:
	templates/standard/fileview_list.tpl
deleted database credentials accidentially commited (after changing them in the production environment)
Merge branch 'unicode-filenames' into SRSoftware-Mix
dded description of unicode-filenames branch