Revert "fix: make requiresArg work in conjunction with arrays (#136)"

[boneskull]

This reverts commit 77ae1d4.

Prior to this commit, those wishing to require that an array-type option has a nonzero amount of arguments could use the check() function for validation.

The commit removed the ability to use nargs in conjunction with array-type options.

After this commit, those wishing to limit the number of values an array-type option accepts have no viable workaround. This also has the implication that such an option cannot be used prior to a positional option, because it's ambiguous:

# usage: script [--foo n1 n2] <stuff>
$ script --foo bar baz quux
# `quux` should be `stuff`, but because `foo` is an array, it eats up `quux`.

UPDATE: Previous to #136, the above example was still an issue, but nargs(1) or requireArg() was a viable workaround; it no longer is.

[boneskull]

@vmx looks like @bcoe will be landing this since #136 introduces problems. I'll let him chime in, but you won't be left high & dry--it sounds like he'll have something to address your use case in the near future.

[bcoe]

@vmx see my comments in #136, this is only a temporary revert.