add .npmignore file to not include sample in npm
mark express and mu2 as devDependencies

these are used for the sample. they are not needed for the library itself.
perhaps consider moving the sample to its own repository
Merge pull request #4 from omsmith/packaging

Packaging
(fix) params is a hash, not an array
Merge pull request #5 from omsmith/params

(fix) params is a hash, not an array
use es5 builtins like Object.keys and Date.now

this is expected to be used in Node.js
any browser beyond IE8 also supports these functions
someone wanting to use it in IE8 can bring in a polyfill
(style) if cond return true => return cond
Merge pull request #6 from omsmith/es5

use es5 builtins like Object.keys and Date.now
Merge pull request #7 from omsmith/style

(style) if cond return true => return cond