restructure for new extraction contract

[actualben]

the contract should be:

• if more than one file is extracted they are always placed into a new subdirectory of the output directory
• if there is only one file extracted it will be extracted into the output directory
• the user may specify --subdir=always, --subdir=never, or the default --subdir=auto to change these behaviors
• by default the output directory is the current working directory, but the user may override this with --outputdir
• the user should be able to specify the name of the single output file OR the name of the output subdirectory with a cli arg - i need to think about the argument structure for this...does --outputpath work?