Modified app to dynamically register backends instead of hard-coding them
Moved dependency check to the individual backends instead of the config

Conflicts:
	apps/files_external/appinfo/app.php
	apps/files_external/lib/config.php
Added cURL dependency check to Google Drive and WebDAV backend
Added check for backend's checkDependencies method to OC_Mount_Config::getBackends() when backend is configured to have some instead of blindly calling it and crashing

Conflicts:
	apps/files_external/lib/config.php
	apps/files_external/lib/google.php
Changed dependency check messages from warnings to notes
Added check for duplicate dependency check messages to display only the first
Added cURL dependency for Amazon S3, Dropbox and SWIFT

Conflicts:
	apps/files_external/lib/amazons3.php
	apps/files_external/lib/swift.php
Moved dependency checks to end of class files
Dependency messages now appear below the configuration options instead of above
Reworked dependency check method to support consolidated messages for multiple backends

Conflicts:
	apps/files_external/lib/google.php
	apps/files_external/lib/swift.php
	apps/files_external/templates/settings.php
Update backends and their configurations
Merge branch 'master' into fs-backend-registration

Conflicts:
	apps/files_external/templates/settings.php
use command -v to detect if smbclient exists
remove duplicate method checkDependencies()
unit tests for dynamic backend registration
Merge pull request #8032 from owncloud/fs-backend-registration

Files External: allow dynamic backend registration