Adds a loose check for credit cards

This patch adds a check that can be used to precheck a creditcard flag before getting it's full number

Sub-tasks (squashed):
- Removing unnecessary grunt npm task (grunt-qunit-istanbul replaces grunt-contrib-qunit)
- Adds test/instrumented to gitignore
- Adds a dry function to normalize the credit card number
- Refactor cardType
- Package.json: updates for strict grunt version and removes nodeunit
- Tests: moving test blocks to js files
- Tests: uses QUnit from NPM
- Tests: refactored all tests
- Also making moip.creditCard to a instanciated object for performance
Merge pull request #3 from estantevirtual/loose-check

Loose creditCard type check and some refactoring