Clippy Fixes & Basename/Cat Fixes

A simple assortment of fixes found by clippy. In addition to these fixes, there is also a fix for basename , cat and cut. For basename, std::process::exit() has a minor cosmetic change to rename it to process::exit(). For cat, the "-" path now works as an alias for stdin, and stdin now may be used with flag arguments. Finally, the tests for cut have been fixed.