Move more common properties to the front of property lists,
so that they can be passed as constructor arguments.
E.g.
parser:option "-p" "--port"
:description "Port number."
:default "8080"
:convert(tonumber)
can now be expressed as
parser:option("-p --port", "Port number.", "8080", tonumber)
Disable undocumented ability to specify aliases as arguments
for constructors, e.g. parser:option("-f", "--foo"), and instead
order properties and pass constructor arguments to them.
E.g. parser:argument("foo", "A foo that bars") sets argument
name to foo and description to "A foo that bars".
TODO: remove "aliases" property, instead allow setting several
names in one string by separating them using space.
TODO: reorder properties so that most useful ones could be used
as constructor arguments.
* Better out-of-the-box behavior: commonly used feature should work without configuration. Only use default value if argument/option was not used at all.
* Add `defmode` field so that old behaviour can be used, too.
