Tidy, delete dead code.

See #35.
See #43.
Notes on string resources.

See #43.
See #35.
Make string resources generally available.

The `Options` object now has a `format` method that will format string
resources using the string resources defined in the usage message
markup.

Closes #43.
See #35.
Thoughts on the state of the project.
Provide format to `abended` function.

Instead of providing the message string and the components of the
message format as arguments, add them to an exception and pass the
exception to the `abended` function. That way, the `abended` function
can simply throw or forward the exception.

With this commit, I've placed the format components into a `format`
object to keep from adding too much to the `Error` object namespace.

Closes #35.
Merge branch `strings` into `master`.