Ability to specify an `appname`

[mikermcneil]

Ability to specify an rc appname as a command-line option instead of providing it inline:

// somescript.js
var conf = require('rc')();

node somescript --rc foo
# will check for more config in .foorc, FOO-* env variables, etc.

Much like the --config option for specifying the location of other config files. It's easy to work around currently, but would be a nice convenience.

[mikermcneil]

Realized about a second after posting this that it's mostly pointless :) Nevermind!