Added download function and changed G option

Added the download function. -g with argument is mandatory. The comma
separated file/folder paths wrt to IDrive will be provided here. This
will then be converted to a temp file. With -G a download location can
be specified, if not given then a location in /tmp will be used.
Changed the delimiter for path in config to comma

The path dleimiter for -g option is comma as semi-colon causes issues in
parsing from command line. To have consistency the delimiter for the
config files have also been changed to comma. Linux filenames can have
comma in them but is generally not used.
Changed for upload list, delete list and upload list again during acl
backup
Added space_usage function and refactored cmd for getting server

Added the space usage function which will display the totaL space and used space in GB and total file count.

Also improved the command used to retrieve the server details.