Added needs option.

Made help page pretty, and added --completion option

Update README.md

Use yargs more. Fix audit failure. Update README.md

Updated tslint

Merge pull request firecow#7 from moberghammer/add-version-option

Added version option

Better error message

Implemented exec and manual "command" arguments

Feature is now done. Update README.md

Removed "extends" from README.md, because is has already been impleme…

…nted