_trueOrNextVal = function (argParts, args) {
    if (argParts[1]) {
      return argParts[1];
    }
    else {
      return (!args[0] || isOpt(args[0])) ?
        true : args.shift();
    }
  }
@constructor
Parses a list of command-line args into a key/value object of
options and an array of positional commands.
@ param {Array} opts A list of options in the following format:
[{full: 'foo', abbr: 'f'}, {full: 'bar', abbr: 'b'}]]