Cleaned up --help output, expanded manpage

* Options list in --help output sorted into natural/priority order
* -p flag added to --help synopsis, documented in manpage
* Manpage SYNOPSIS section formatting is now more robust/canonical
* Ordered usage, options list in manpage to match --help message
* Added EXAMPLES from README.md to man page
* Minor copyediting/expansion of documentation and help
Typo

Remove a spurious colon from EXAMPLES
Merge pull request #38 from ferdnyc/doc-fixes

Cleaned up --help output, expanded manpage