Fix AmazonS3 rmdir on the root
Fix amazon s3 rename overwrite
Fix copy overwrite for amazon s3
Skip test for unsuported feature for amazon s3
Inject config into checkserver and cleanup tests
Don't complain about non-writable datadirs before we're installed
Check for writable datadir during setup
Don't test for htaccess if we cant write into the datadir anyway
group shares and combine permissions
unit tests for grouping of shares pointing to the same source
Show login again instead of JSON if CSRF check fails

Previously a JSON error page was shown to the user in-case the CSRF token was not valid. This was confusing and prevented people from login.

With this at least the login page is shown again and not a JSON error message. I consider this as sufficient since adding a new error page just for this sake would uneededly make lib/base.php even more cluttered and this is a edge-case which optimally should anyways not happen that often.

This can be tested by opening the login page, then clearing the cookies, and trying to login.
user/backed: use pow of two for backed action constants

the current implementation limits number of possible backed actions
to 8 as it uses pow of 16 for constants. This change introduces pow
of two and allows up-to 32 actions to be defined.

The old values are preserved for backward compatibility.
autotest.sh shall not terminate if mysql db could not be dropped
Drop only if exists
generateTarget() will always find a unique target
fix add user to group to work with grouped shares
fix unit tests
mark exclude list as deprecated. It neither used by the files app nor by the
calendar or contacts app. It doesn't make sense to build a exclude list by the
share API, the apps knows best which are valid targets.
only add a new row if it isn't a unique share, otherwise update the existing row
clear share table after each test run