bugfix: conf to config

I think I found a tiny typo.

Invocation per README.md instructions resulted in:

    TypeError: Cannot read property 'scripts' of undefined

Adding a "console.log(JSON.stringify(pkg));" displayed something like:

    {"_cache":{},"_hooks":{"before scripts":[null]},"_files":{},"_js":"","urlPrefix":"","copy":false,"dir":"xxx","root":true,"basename":"xxx","globalLookupPaths":["xxx/components"],"lookupPaths":[],"ignored":{"scripts":["xxx"],"styles":[],"files":[],"images":[],"fonts":[]},"config":{"name":"xxx","version":"0.0.0","dependencies":{"xxx":"0.0.0"},"scripts":["xxx.coffee"],"paths":[]},"_events":{},"assetsDest":"build"}

The "conf" property is absent, and "config" is existent.