alternate bogart viewengine signature

bogart-jade-alternate.js

var bogart = require('bogart')
  , jade   = require('jade')
  , when   = bogart.q.when;

require('bogart').viewEngine.addEngine('jade', function(read, cache, opts) {
  return when(read(), function(tpl) {
    var fn;

    if(typeof tpl === "function") {
      fn = tpl;
    } else {
      fn = jade.compile(tpl, opts);
      cache(fn);
    }
    return fn(opts.locals);
  });
});