Bump deps / Remove .npmignore / Use istanbul-coveralls

* I updated the dependencies and devDependencies.
  * [minimatch](https://github.com/isaacs/minimatch) v2.0.1 has been released.
* I removed `.npmignore` file because the package.json has `files` field.
* I introduced [istanbul-coveralls](https://github.com/shinnn/istanbul-coveralls) to the `coveralls` command.