Extract Command, Various Fixes, Minor Cleaning

open command changed to read for clarity; about command added and
implemented; extract command added; all formats can now extract all
their files to a specific folder via the extract command, use about
command to see more information; various comments clarified and all
comments placed in a more similar position; invalid file error message
clarified to file not found; Removed a vague write error, will need to
add more specific write error try excepts later during testing.