* add comments to explain use of the token file
* only pass current env to the ajax call (it is enough to load the corresponding config file and get everything we need !)
* DBRestore : initialize user & pwd as needed
* DBRestore : do not throw Exception anymore but only BackupException
SVN:trunk[5659]
* use centralized constants instead of literal values in code
* remove config parameters 'db_character_set' and 'db_collation'
* always fix charset when creating/altering column
* backup : use utf8mb4 only for mysqldump >= 5.5.33 (was introduced in 5.5.3 but only available in 5.5.33 for programs)
SVN:trunk[5443]
