ls.go: Continuing Evolution

Yet another huge improvement.
* Goroutines for a slight performance boost by making the entire statistics-gathering process threaded
* Obtaining user/group names is currently disabled until I figure out how to fix the performance
* Functions are rewritten and re-organized to be significantly clutter-free.
* All file lists are moved to be universally available to all functions, as critical as they are.
* Comment improvements
* Symbolic links are now followed, colored, and printed in long mode.