Refactor: rename output to parseCommandLine.
Add -version command line option.
Add too-many-command-line-arguments check.
Make assertEquals output easier to read.
Merge branch 'fix_assert_output' into add_version_flag
Refactor parseCommandLine.
Extract CommandLineParser to its own file.
Improve test to show program name is printed.
Move User and RealUser into model package.
Move CommandLineParse into into usage package.