correct --serve example in documentation.  appending --serve arg with port creates base_dir with port name as deploy_dir.
pass in port parameter with hypen [-1234] to not be passed as arg, then manipulate string and strip hypen so it passes as an int type
WIP - first pass at implementing an autoreload option.  Added
a files_changed() and get_extensions() def.

This essentially makes the --serve arg useless as the way it's
structured right now, it will run httpd.serve_forever() and
not have the chance to do site.prepare() or site.run() again.
Also, need to think about how to properly get changed files as
it will continuously loop and autoreload every second because
shutil.copy changes the file modification time.
Ignore the `_deploy` directory in files_changed() and get_extensions().

This will make sure that any files changed (not in the _deploy dir) will
trigger site.prepare() and site.run(). If it didn't ignore the _deploy dir,
files_changed would run site.prepare() and site.run() every second.
[README] Autoreload arg documentation and usage examples.
Remove TODO at top of file.
Merge remote-tracking branch 'upstream/master'