Deprecate older API wrappers and calls

Those old classes have now non-static pendants and can be deprecated IMHO.
Fix case-sensitivity
Don't disclose relative directory path for single shared files of user

The "dir" key is used within the public sharing template to indicate in which directory the user currently is when sharing a directory with subdirectories. This is needed by the JS scripts.

However, when not accessing a directory then "dir" was set to the relative path of the file (from the user's home directory), meaning that for every public shared file the sharee can see the path.
(For example if you share the file "foo.txt" from "finances/topsecret/" the sharee would still see the path "finances/topsecret/" from the shared HTML template)

This is not the excpected behaviour and can be considered a privacy problem, this patch addresses this by setting "dir" to an empty key.
Remove unused variable and make Scrutinizer happy.
add postfix

add postfix
Remove exec() call with invalid name on windows

Currently running unit tests prints the following message 3 times:
The command "command" is misspelt or could not be found.
Instead of trying this, we just skip this now.
Deduplicate function by moving it to the OC_Helper
Simplify the binary finding code in the movie preview class
Clean up the test data in tearDownAfterClass()

The result of the listener should then be empty and can be removed
Remove testcleanuplistener.php
detect user display name attribute and return user count depending on its presence
consolidate user count filter in wizard and user back end
detectors (email, displayname..) are now started in one place, triggered from only 2 places. more reliable structure and flow, saves requests
to reassure that selected attributes still work, do not count all matching entries but limit it to 1 in order to make it faster
a corrected email attribute needs to be saved, not only returned
JS doc
this happens already before counting, no need anymore
use underscore.js for undefined checks
better readbility, no effective changes
phpdoc and mixed up letters