Merge pull request #5 from ruyadorno/grunt-bump

Added grunt release task
Update README.md
Fix bug of target="_blank"
Fix .gitignore
Fix bug of taget="_blank"
* optimize class structure
Merge branch 'master' of https://github.com/marloscarmo/data-metrics

Conflicts:
	example/index.html
	src/data-metrics.js
* optimize class structure
* fix README.md file
* change methods names
* builded version
Added README file to list of updated files on release