To give user a possibility to choose what archiver he can use another
options was introduced for cd32 and archive wrapper modules. This option
will indicate what archiver should be used for compressing the save
state directories.
Also, new command was added to utils - run_command which is an
generalized subprocess.call function.
Requirements is now added with module six, which was needed to detect
string-like objects in sane way.
Added safe guards for get_config function, introduced CmdOption class
for convenient accessing options as a dict keys with option to make them
as a list of commandline options suitable for passing to fs-uae.
