folderman: make escapeAlias public as its now used in accountmigrator.
cfg migration: Add a account migrator class.
mirallconfigfile: Properly use the USE_THEME macro.
ownCloud Theme: Implement appName() and appNameGUI().
Account: Add a wasMigrated flag.

If an account in a branded client was migrated from a former ownCloud
configuration, the method wasMigrated() will return true.
FolderMan: Migrate folderlist if no folder definitions can be found

and the account indicates that it was migrated. In that case,
read the folder definitions from the ownCloud config directory.
Account: Read settings from ownCloud config if no branded exists.

If there is not yet a config for a branded client, but one for the
"normal" client targetting the same URL, it will be migrated.