Try connection with specified db when postgres does not work

Move maintenance start to ajax call

files_encryption: bug fixes for reported problems.

Conflicts:
	lib/util.php

use executeAudited in files cache

minor cleanup for exception handling

Revise Contributing document

Make templates aware of different owncloud editions

check if the decrypted private key is valid on login and on read/write files

Conflicts:
	apps/files_encryption/appinfo/app.php
	apps/files_encryption/lib/util.php

Fix files_encryption app upgrade from 4.5 to 5.0

Folders with multiple periods problem fix

make sure that only one process can enter the migration mode

Merge branch 'files_encryption_upgrade_fix' of github.com:owncloud/core into files_encryption_upgrade_fix

remove App management top bar and move buttons more contextually in the interface

Conflicts:
	apps/files_encryption/tests/crypt.php

Multiselect fixes