Update dependencies and devDependencies

* sinon, rimraf, async and hashdir are unused.
* should#include has been removed.

https://github.com/shouldjs/should.js/commit/c17cd50777e49a556381ef71bac
69d1e98255012
Remove redundant rules

They are ignored by default.
Merge pull request #19 from shinnn/master

Update dependencies / Fix .npmignore