- fixed bug in SshAccessedMysqlDb which didn't handle the fields with is_autoinc_index properly
- fixed bug in SshAccessedMysqlDb which failed when a field description contained double quotes
- improved SshAccessedMysqlDb.query(), which now displays the error message on failure
- fixed bug in SshAccessedMysqlDb.table_exists,which failed when the table didn't exist.
work related to [https://bugzilla.ipr.univ-rennes.fr/show_bug.cgi?id=3958]
- added to the class `ISqlDatabaseBackend` the ability to delete a sql table
- also added `SshAccessedMysqlDb`: an implementation of `ISqlDatabaseBackend` that implements the sql database as a remote sql database accessed using ssh
- added unit tests to validate the backends SshAccessedMysqlDb and SqliteDb
work related to [https://bugzilla.ipr.univ-rennes.fr/show_bug.cgi?id=3958]