AutoMySQLBackup

The attached patch against version 2.5 enables the variables to be set in 3
different ways:
- in a config file in the same folder as the script (file should be named
$0.config, e.g. if the script is automysqlbackup.sh the config would be
automysqlbackup.sh.config)
- in a config file in the /etc folder (/etc/automysqlbackup.config)
- from within the file itself (original option)

Patch is in diff -uwb format.

Thanks.